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Informix Guide to SQL: Syntax, Version 6.0

1. The DEFAULT Clauses DEFAULT Clause DEFAULT literal p 5 NULL f CURRENT A p 1 440 DATETIME Field Qualifier p 1 428 TODAY J p 1 439 SITENAME J p 1 438 XP DBSERVERNAME _ p 1 438 literal represents a literal default value The default value is inserted into the column when an explicit value is not specified If a default is not specified and the column allows nulls the default is NULL If you designate NULL as the default value for a column you cannot use the keywords NOT NULL as part of the column definition You cannot designate default values for serial columns If the column is of type TEXT or BYTE you can designate only nulls as the default value 1 88 Syntax CREATE TABLE Literal Terms as Default Values You can designate literal terms as default values A literal term is a string of character or numeric constant characters that you define To use a literal term as a default value follow these rules Use the Literal With Columns of Type INTEGER INTEGER SMALLINT DECIMAL MONEY FLOAT SMALLFLOAT DECIMAL DECIMAL MONEY FLOAT SMALLFLOAT CHARACTER CHAR NCHAR NVARCHAR VARCHAR DATE INTERVAL INTERVAL DATETIME DATETIME e Characters must be enclosed in quotation marks Date literals must be of the format specified by the DBDATE environment variable If DBDATE is not set the format mm dd yyyy is assumed
2. FROM Clause Table p FROM Name 1 p 1 309 table F X _ Adaitional J View alias Tables Name p 1 510 Synonym as Name p 1 504 Additional Tables J ie D table Ei alias as Table Koo o OUTER Name A peter table a View alias Name p 1 510 AS Synonym Name p 1 504 Table OUTER Name p 1 506 TER re table Additional A alias Tables p 1 510 AS Synonym Name p 1 504 table alias is a name that you attach to the table within the scope of the SELECT statement Syntax 1 323 SELECT 1 324 Syntax Use the keyword OUTER to form outer joins Outer joins preserve rows that otherwise would be discarded by simple joins See Chapter 3 of the Informix Guide to SQL Tutorial for more information on outer joins You can supply an alias for a table name You can use the alias to refer to the table in other clauses of the SELECT statement This is especially useful with a self join See the WHERE clause on page 1 325 for more information about self joins The following example shows typical uses of the FROM clause The first query selects all the columns and rows from the customer table The second query uses a join between the customer and orders table to select all customers who have placed orders SELECT FROM customer SELECT fname lname order_num FROM customer orders WHERE customer customer_num orders custom
3. Syntax ZEA connect ro Database Ea a aun EE E CO E CO connection AS name g USER Clause conn_nm y AS variable Bele DEFAULT A E C E CO ne S WITH CONCURRENT TRANSACTION connection name is a quoted string that identifies the connection It is case sensitive and must conform to the same rules as any identifier See Identifier on page 1 469 conn_nm variable isan ESQL C or ESQL COBOL character type host variable that holds the connection name The connection name is not case sensitive and must conform to the same rules as any identifier as described in the Identifier segment See Identifier on page 1 469 Usage The CONNECT statement connects the application to a database environment The database environment can be a database a database server or a database and a database server If the application successfully connects to the specified database environment the connection becomes the current connection for the application SOL statements fail if no current connection exists between an 1 44 Syntax CONNECT application and a database server If you specify a database name the database server opens the database You cannot use the CONNECT statement in a PREPARE statement An application can connect to several database environments at the same time and it can establish multiple connections to the same database environ ment provided each connection has a unique conne
4. Execute SQL statements in connection C starting transaction ah EXEC SQL SET CONNECTION B switch to connection B Execute SQL statements starting a transaction in B Now there are two active transactions one each in B Syntax 1 47 CONNECT Figure 1 1 1 48 Syntax AN and C 7 EXEC SQL SET CONNECTION A switch to connection A Execute SQL statements starting a transaction in A Now there are three active transactions one each in A B and C EXEC SQL SET CONNECTION C ERROR transaction active in A SET CONNECTION C fails current connection is still A The transaction in A must be committed rolled back since connection A was started without the CONCURRENT TRANSACTION clause EXEC SQL COMMIT WORK commit tx in current connection A Now there are two active transactions in B and in C which must be committed rolled back separately EXEC SQL SET CONNECTION B switch to connection B EXEC SQL COMMIT WORK commit tx in current connection B EXEC SQL SET CONNECTION C go back to connection C EXEC SQL COMMIT WORK commit tx in current connection C EXEC SQL DISCONNECT ALL ESQLIC code showing the WITH CONCURRENT TRANSACTION clause Warning When an application uses the WITH CONCURRENT TRANSACTION clause to establish multiple connections to the same d
5. C DISTINCT PRIMARY o KEY CHECK Clause p 1 98 Temporary table column constraints are the same as column constraints for regular tables except that you cannot place referential constraints on columns in a temporary table In other words temporary columns cannot be refer enced or referencing columns The following constraint definition keywords cannot be used when you are creating a temporary table REFERENCES CONSTRAINT For more information about column constraints in regular tables see Column Level Constraint Definition Option on page 1 91 Syntax 1 103 CREATE TABLE Table Level Constraint for Temporary Tables Temp Table Table Level Constraint KEY UNIQUE tT KS DISTINCT PRIMARY J ees gt CHECK Clause p 1 98 Table level constraints are defined for temporary tables in the same manner as regular database tables However you cannot place referential constraints on columns in a temporary table In other words temporary columns cannot be referenced or referencing columns The following table constraint definition keywords cannot be used when you are creating a temporary table FOREIGN KEY REFERENCES CONSTRAINT For more information on table level constraint definition options see The Constraint Definition Option on page 1 92 WITH NO LOG Option for Temporary Tables 1 104 Syntax You must use the WITH NO LOG k
6. View Name p 1 510 Ta column is a column belonging to Table Name Synonym Name or View Name You must specify column names if you are not loading data into all c olumns in the table synonym or view delimiter is a quoted string constant that contains the character to use as the delimiting character in the load file filename is a quoted string constant or character string that specifies the file that contains the data to load It includes the pathname of an operating system file The LOAD statement appends existing data new rows to the table It does not overwrite Syntax 1 255 LOAD You cannot add a row that has the same key as an existing row To use the LOAD statement you must have Insert privileges for the table into which you want to insert the data For information on database level and table level privileges see the GRANT statement on page 1 231 The LOAD FROM File The LOAD FROM file is the file that contains the data to add to a table You can use the file created by the UNLOAD statement as the LOAD FROM file If you do not include a list of columns in the INSERT INTO clause the fields in the file must match the columns specified for the table in number order and type Each line of the file must have the same number of fields You must define field lengths that are less than or equal to the length specified for the corre sponding column Specify only values that can conve
7. called variable a a p 1 430 _ called _ variable is the name of one of the arguments expected by the called procedure Procedure arguments are bound to procedure parameters by name or position but not both That is you can use the parameter name syntax for none or all of the arguments specified in the procedure call expression Some typical procedure call expressions are shown in the following example read_address Miller read_address lastname Miller Identifier Identifier Purpose Use the Identifier segment in the following segments to specify the name of a database object Column Name Connection Name Constraint Name e Database Name Index Name e Procedure Name e Synonym Name e Table Name e Trigger Name e View Name Syntax letter p aee c letter digit underscore digit is an integer from 0 to 9 letter is an uppercase or lowercase character from a to Z underscore is the underscore _ character Syntax 1 469 Identifier Usage An identifier can contain up to 18 characters inclusive Database names are limited to 10 characters Do not declare any reserved word as an identifier of your application development tool or SQL API NLS With NLS enabled you can use foreign characters in names of database objects such as databases tables and views as shown in the following example CREATE DATABASE march
8. Results in error The following example does not produce an error when the database server tries to execute the update line exec sql declare q_curs cursor for select customer_num fname lname from customer where lname matches last_name for update exec sql open q_curs exec sql begin work exec sql fetch q_curs into cust_rec fetch after begin exec sql update customer set lname Smith where current of q_curs no error exec sql commit work Runs successfully DECLARE When you update a row within a transaction the row remains locked until the cursor is closed or the transaction is committed or rolled back If you update a row when no transaction is in effect the row lock is released when the modified row is written to disk If you update or delete a row outside a transaction you cannot roll back the operation A cursor declared for insert is an insert cursor In a database that uses transactions you cannot open an insert cursor outside a transaction unless it also was declared with hold Subset of INSERT Associated with a Sequential Cursor You create an insert cursor by associating a sequential cursor with a restricted form of the INSERT statement The INSERT statement must include a VALUES clause it cannot contain an embedded SELECT statement The following example contains INFORMIX ESQL C code that declares an insert cursor exec sql declare ins_cur cursor for insert into stock
9. column name is the name of a column variable name is a program variable or a host variable that contains a character string Syntax 1 453 Expression The LENGTH function returns the length of a character column not including any tra returns illustra iling spaces With TEXT or BYTE columns the LENGTH function the full number of bytes in the column The following example tes the use of the LENGTH function SELECT customer_num LENGTH fname LENGTH lname LENGTH How many bytes is this FROM customer WHERE LENGTH company gt 10 You can use the LENGTH function to return the length of a character variable Time Functions Time Functions 1 454 Syntax non date a EN N DATE expression _ gt date DAY datetime expression MONTH WEEKDAY YEAR date EXTEND datetime N i pee gt first TO last month day year SS MDY integer integer integer A expression expression expression date datetime is an expression as defined on page 1 430 that evaluates expression to a DATE or DATETIME value day integer is an expression as defined on page 1 430 that evaluates expression to an integer between 1 and 28 29 30 or 31 as appropriate for the month Expression first is a qualifier that specifies the first field in the result It can be any DATETIME qualifier as defined on page 1 428 as long as first
10. FOR i I 1 TO limit RETURN i WITH RESUME END FOR IF backwards 0 THEN RETURN END IF FOR i IN limit TO 1 RETURN i WITH RESUME END IF END PROCEDURE sequence SPL Statements 2 39 SYSTEM SYSTEM Purpose Use the SYSTEM statement to make an operating system command run from within a procedure Syntax SYSTEM character expression 3 character variable character expression is any expression that is a user executable operating system command character variable is a variable that contains a valid operating system command Usage If the supplied expression is not a character expression expression is converted to a character expression before the operating system command is made The complete character expression passes to the operating system and executes as an operating system command The operating system command specified by the SYSTEM statement cannot run in the background The database server waits for the operating system to complete execution of the command before continuing to the next procedure statement Your procedure cannot use a value or values returned by the command If the operating system command fails that is if the operating system returns a nonzero status for the command an exception is raised containing the returned operating system status as the ISAM error code and an appropriate SQL error code In both DBA privileged and owner privileged procedures that cont
11. Mary uses her new privilege to grant Cathy and Paul access to the table GRANT SELECT UPDATE ON items TO cathy GRANT SELECT ON items TO paul Later you issue the following statement to cancel Mary s access privileges on items REVOKE SELECT UPDATE ON items FROM mary This single statement effectively revokes all privileges on the items table from Mary Cathy and Paul If you want to create a chain of privileges with some other user as the source of the privilege use the AS grantor clause AS grantor The AS grantor clause lets you establish a chain of privileges with another user as the source of the privileges In so doing you relinquish your ability to break the chain of privileges Even a DBA cannot revoke a privilege unless GRANT that DBA originally granted the privilege The following example illustrates this situation You are the owner of the items table and you grant all privileges to Tom along with the right to grant all privileges REVOKE ALL ON items FROM PUBLIC GRANT ALL ON items TO tom WITH GRANT OPTION You also grant Select and Update privileges to Jim but you specify that the grant is made as Tom This means that the records of the database server shows that Tom is the grantor of the grant in the systabauth system catalog table rather than you GRANT SELECT UPDATE ON items TO jim AS tom Later you decide to revoke Tom s privileges on the items tab
12. HAVING Clause Condition gt HAVING p 1 404 p In the following examples each condition compares one calculated property of the group with another calculated property of the group or with a con stant The first SELECT statement uses a HAVING clause that compares the calculated expression COUNT with the constant 2 The query returns the average total price per item on all orders that have more than two items The second SELECT statement lists customers and the call months if they have made two or more calls in the same month SELECT order_num AVG total_price FROM items GROUP BY order_num HAVING COUNT gt 2 SELECT customer_num EXTEND call_dtime MONTH TO MONTH FROM cust_calls GROUP BY 1 2 HAVING COUNT gt 1 You can use the HAVING clause to place conditions on the GROUP BY column values as well as on calculated values The following example returns the customer_num call_dtime in full year to fraction format and cust_code and groups them by call_code for all calls that have been received from customers with customer_num less than 120 SELECT customer_num EXTEND call_dtime call_code FROM cust_calls GROUP BY call_code 2 1 HAVING customer_num lt 120 SELECT The HAVING clause generally complements a GROUP BY clause If you use a HAVING clause without a GROUP BY clause the HAVING clause applies to all rows that satisfy the query Without a GROUP B
13. If a row is returned successfully the RETURNED_SQLSTATE field of GET DIAGNOSTICS contains the value 00000 representing success If no row is found the preprocessor sets the SQLSTATE code to 02000 which indicates no data found and the current row is unchanged Five conditions set the SQLSTATE code to 02000 indicating no data founa as described in the following list The active set contains no rows e You issue a FETCH NEXT statement when the cursor points to the last row in the active set or points past it You issue a FETCH PRIOR or FETCH PREVIOUS statement when the cursor points to the first row in the active set e You issue a FETCH RELATIVE n statement when no nth row exists in the active set e You issue a FETCH ABSOLUTE n statement when no nth row exists in the active set See the GET DIAGNOSTICS statement in this manual for more information You can also use SQLCODE of sqlca to determine the same results See the Informix Guide to SQL Tutorial for further information about SQLCODE of sqlca References See the ALLOCATE DESCRIPTOR CLOSE DEALLOCATE DESCRIPTOR DECLARE DESCRIBE GET DESCRIPTOR OPEN PREPARE and SET DESCRIP TOR statements in this manual for further information about using the FETCH statement with dynamic management statements In the Informix Guide to SQL Tutorial see the discussion of the FETCH statement in Chapter 5 For further information about error checking and the
14. In the following example the procedure uses an IF statement with both an ELIF clause and an ELSE clause The IF statement compares two strings and displays a 1 to indicate that the first string comes before the second string alphabetically or a 1 if the first string comes after the second string alphabetically If the strings are the same a 0 is returned 2 24 SPL Statements IF CREATE PROCEDURE str_compare strl CHAR 20 str2 CHAR 20 RETURNING INT DEFINE result INT IF strl gt str2 then result 1 ELIF str2 gt stri THEN result 1 ELSE result 0 END IF RETURN result END PROCEDURE str_compare The ELIF Clause Use the ELIF clause to specify one or more additional conditions to evaluate If you specify an ELIF clause and the IF condition is false the ELIF condition is evaluated If the ELIF condition is true the statements following the ELIF clause execute The ELSE Clause The ELSE clause executes if no true previous condition is in the IF clause or any of the ELIF clauses Conditions in an IF Statement Conditions in an IF statement are evaluated in the same way as conditions in a WHILE statement If any expression contained within the condition evaluates to null then the condition automatically becomes not true Consider the following points 1 Let the expression x evaluate to null Then x is not true by definition Furthermore not x is also not true 2 The sole operato
15. K FROM variable I W name indicator variable INDICATOR ndicator variable cursor id cursor variable descriptor descriptor variable descriptor USING SQL DESCRIPTOR L descriptor variable a DESCRIPTOR sqida is the identifier of a cursor declared for an INSERT statement pointer is an embedded variable name that identifies a cursor declared for an INSERT statement is a quoted string that identifies a system descriptor area allocated with the ALLOCATE DESCRIPTOR statement is an embedded variable name that identifies a system descriptor area allocated with the ALLOCATE DESCRIPTOR statement indicator variable is a program variable that receives a return code if null data sqlda pointer 1 284 Syntax is placed in the corresponding data variable points to an sqlda structure representing values that correspond to the question mark placeholders in a prepared INSERT statement Usage X O PUT variable name is a program variable whose contents are to replace a question mark placeholder in a prepared INSERT statement Each PUT statement stores a row in an insert buffer that was created when cursor name was opened If the buffer has no room for the new row when the statement executes the buffered rows are written to the database in a block and the buffer is emptied As a result some PUT statement executions cause rows to be written to the d
16. N 30 Index LANG environment variable 4 49R LC_COLLATE environment variable 4 50R LC_CTYPE environment variable 4 51R LC_MONETARY environment variable 4 52R LC_NUMERIC environment variable 4 53R LC_TIME environment variable 4 53R NCHAR data type 3 17R NVARCHAR data type 3 18R populating with dbimport 5 18R setting environment variables 1 16R 4 44R specifying a language environment 25 viewing characteristics of 1 18R LS Database description of 1 16T LS database versus non NLS database 1 19R ondecomposable attributes 8 15T onsequential access See Disk access nonsequential ormal form 8 29T ormalization benefits 8 29T first normal form 8 29T of data model 8 29T rules 8 29T rules summary 8 32T second normal form 8 31T third normal form 8 32T OT CLUSTER keywords syntax in ALTER INDEX 1 12S use in ALTER TABLE 1 13S OT FOUND keywords in the WHENEVER statement 1 398S 1 400S OT IN keywords use in Condition subquery 1 4145 OT keyword syntax in Condition segment 1 404S 1 405S with BETWEEN keyword 1 3275 with IN keyword 1 329S use in Condition segment 1 410S with LIKE MATCHES keywords 1 328S NOT logical operator 2 36T NOT NULL keywords syntax in ALTER TABLE 1 178 in CREATE TABLE 1 888 use in ALTER TABLE 1 278 in CREATE TABLE 1 908 9 24T with IS keyword 1 327S NOT operator condition 1 405S NOT relational operator 2 32T NOT WAIT keywords in SET LOCK MODE 1 370S NULL keyword ambiguous as procedure va
17. All rights reserved No part of this work covered by the copyright hereon may be reproduced or used in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without permission of the publisher Published by INFORMIX Press Informix Software Inc 4100 Bohannon Drive Menlo Park CA 94025 INFORMIX and C ISAM are registered trademarks of Informix Software Inc UNIX is a registered trademark licensed exclusively by the X Open Company Ltd in the United Kingdom and other countries X Open is a registered trademark of X Open Company Ltd in the United Kingdom and other countries PostScript is a registered trademark of Adobe Systems Incorporated IBM is a registered trademark and DRDA is a trademark of International Business Machines Corporation Some of the products or services mentioned in this document are provided by companies other than Informix These products or services are identified by the trademark or servicemark of the appropriate company If you have a question about one of those products or services please call the company in question directly Documentation Team Bob Berry Mary Cole Sally Cox Signe Haugen Geeta Karmarkar Catherine Lyman Judith Sherwood Rob Weinberg Chris Willis Eileen Wollam RESTRICTED RIGHTS LEGEND The Informix software and accompanying materials are provided with Restricted Rights Use
18. Syntax 1 381 UNLOCK TABLE References See the COMMIT WORK ROLLBACK WORK and LOCK TABLE statements in this manual 1 382 Syntax UPDATE UPDATE Purpose Syntax UPDATE Usage Table SET Clause iMate set Sor as Use the UPDATE statement to change the values in one or more columns of one or more rows in a table or view Condition WHERE View ma p 1 404 Name sable PsP Synonym Waite ke CURRENT OF cursor name cursor name is the cursor identifier To update data in a table you must either own the table or have the Update privilege for the table see the GRANT statement on page 1 231 To update data in a view you must have the Update privilege and the view must meet the requirements explained in Updating Rows Through a View on page 1 384 If you omit the WHERE clause all rows of the target table are updated If you are using effective checking and the checking mode is set to IMMEDIATE all specified constraints are checked at the end of each UPDATE statement If the checking mode is set to DEFERRED all specified constraints are not checked until the transaction is committed If you omit the WHERE clause and are in interactive mode DB Access does not run the UPDATE statement until you confirm that you want to change all rows However if the statement is in a command file and you are running from the command line the statement execu
19. syntax 1 1215 WHEN condition 1 121S correlation name in 1 125S 1 128S FOR EACH ROW 15 8T generating an error message 15 14T in client server environment 1 133S in relation to triggering statement 15 6T list AFTER 1 117S BEFORE 1 116S FOR EACH ROW 1 116S for multiple triggers 1 117S sequence of 1 116S merged 1 117S preventing overriding 1 1325 statements 15 3T tracing 15 12T using 15 7T using stored procedures 15 10T WHEN condition 1 1215S 15 10T Triggering statement affecting multiple rows 1 117S execution of 1 113S guaranteeing same result 1 112S result of 1 1235 UPDATE 1 115S Triggering table action on 1 127S and cascading triggers 1 131S Trigonometric function ACOS function 1 460S ASIN function 1 460S ATAN function 1 460S ATAN2 function 1 461S COS function 1 459S SIN function 1 459S TAN function 1 460S TRUNC function syntax in expression 1 4445 use in expression 1 447S Truncation signalled in SQLAWARN 5 12T Two phase commit 12 20T TYPE field changing from BYTE or TEXT 1 359S setting in SET DESCRIPTOR 1 356S setting in X Open programs 1 357S with X Open programs 1 213S Typographical conventions Intro 5R Intro 5S 5T U Unbuffered logging 9 22T Underscore _ wildcard in Condition segment 1 410S UNION operator description of 3 43T display labels with 3 48T restrictions in view 11 22T restrictions on use 1 344S syntax in SELECT 1 310S use in SELECT 1 344S Unique constraint dropping 1 32S modifyin
20. A referential constraint can be established between two tables or within the same table For example you can have an employee table where the emp_no column uniquely identifies every employee through an employee number The mgr_no column in that table contains the employee number of the man ager who manages that employee In this case mgr_no is the foreign key or child that references emp_no the primary key or parent A referential constraint must have a one to one relationship between referencing and referenced columns In other words if the primary key is a set of columns then the foreign key also must be a set a columns that CREATE TABLE corresponds to the primary key The following example creates two tables The first table has a multiple column primary key and the second table has a referential constraint that references this key CREATE TABLE accounts acc_num INTEGER acc_type INTEGER acc_descr CHAR 20 PRIMARY KEY acc_num acc_type CREATE TABLE sub_accounts sub_acc INTEGER PRIMARY KEY ref_num INTEGER NOT NULL ref_type INTEGER NOT NULL sub_descr CHAR 20 FOREIGN KEY ref_num ref_type REFERENCES accounts acc_num acc_type In this example the foreign key of the sub_accounts table ref_num and ref_type references the primary key acc_num and acc_type in the accounts table If during an insert you tried to insert a row into the sub_accounts table whose value for ref_num and
21. ESQL C Programmer s Manual for detailed information about dynamically executing a stored procedure Permitted Statements 1 276 Syntax You can prepare any single SQL statement except the ones in the following list ALLOCATE DESCRIPTOR GET DESCRIPTOR CHECK TABLE GET DIAGNOSTICS CLOSE INFO CONNECT LOAD DEALLOCATE DESCRIPTOR PUT DECLARE OPEN DESCRIBE OUTPUT DISCONNECT PREPARE EXECUTE IMMEDIATE REPAIR TABLE PREPARE EXECUTE SET CONNECTION FETCH SET DESCRIPTOR FLUSH UNLOAD FREE WHENEVER You can prepare a SELECT statement If the SELECT statement includes the INTO TEMP clause you can execute the prepared statement with an EXECUTE statement If it does not include the INTO TEMP clause the statement returns rows of data Use DECLARE OPEN and FETCH cursor statements to retrieve the rows A prepared SELECT statement can include a FOR UPDATE clause This clause normally is used with the DECLARE statement to create an update cursor The following example shows a SELECT statement with a FOR UPDATE clause in INFORMIX ESQL C sprintf up_query Ss s s select from customer where customer_num between and for update exec sql prepare up_sel from up_query exec sql declare up_curs cursor for up_sel exec sql open up_curs using low_cust high_cust Restrictions for Multistatement Prepares You cannot use the following statements in addition to the ones listed in Permitted Statements
22. EXEC SQL insert into sec_tab select DBINFO sqlca sqlerrdl1 from sec_tab where partnum 6 This example inserts a row containing a primary key serial value into the fst_tab table and then inserts the same serial value into the sec_tab table using the DBINFO function The value returned by the DBINFO function is the serial value of the last row inserted into fst_tab Note that the subquery in the last line contains a WHERE clause so that a single value is returned Using the sqlca sqlerrd2 Option The sqlca sqlerrd2 option returns a single integer that provides the number of rows processed by SELECT INSERT DELETE UPDATE and EXECUTE PRO CEDURE statements You can use this option anywhere within SQL statements and stored procedures This option also applies to all SQL APIs To ensure valid results use this option after SELECT and EXECUTE PROCEDURE statements have completed executing In addition if you use this option within cursors make sure that all rows are fetched before the cursors are closed to ensure valid results Expression The following example shows a stored procedure that uses the sqlca sqlerrd2 option to determine the number of rows deleted from a table REATE PROCEDURE del_rows pnumb int ETURNING int Da DEFINE nrows int DELETE FROM sec_tab WHERE partnum pnumb LET nrows DBINFO sqlica sqlerrd2 RETURN nrows END PROCEDURE Exponential and Logarithmic Functio
23. References In the Informix Guide to SQL Tutorial see the discussions of views and security in Chapter 11 Syntax 1 511 View Name 1 512 Syntax SPL Statements Chapter Overview 3 CALL 3 CONTINUE 6 DEFINE 7 EXIT 14 FOR 16 FOREACH 20 IF 24 LET 28 ON EXCEPTION 31 RAISE EXCEPTION 36 RETURN 38 SYSTEM 40 TRACE 42 WHILE 46 2 2 SPL Statements Chapter Overview This chapter contains the Stored Procedure Language SPL statements For additional information about using stored procedures see Chapter 14 of the Informix Guide to SQL Tutorial CALL Purpose Use the CALL statement to execute a procedure from within a stored procedure Syntax Procedure CALL Name p 1 495 4 J Argument RETURNING Ce ee variable Argument Expression gt p 1 430 Lo parameter ye name SELECT Statement Subset p 2 4 parameter name is the name of the parameter as defined by its CREATE PROCEDURE statement Procedure arguments are bound to procedure parameters by name or position but not both That is you can use the parameter name SPL Statements 2 3 CALL syntax for none or all the arguments specified in one CALL statement procedure variable is the name of a variable as defined by its CREATE PROCEDURE statement Usage The CALL statement invokes a procedure called procedure name The CALL statement is identical in behavior to
24. See ANSI AND keyword syntax in Condition segment 1 404S use in Condition segment 1 417S with BETWEEN keyword 1 327S AND logical operator 1 417S 2 36T ANSI 1 15T ANSI compliance determining 1 10R table naming 1 296S ANSI compliance ansi flag 4 15R Intro 7S 1 785 1 855 1 137S described 1 9R list of SQL statements 1 75 reserved words 1 470S updating rows 1 385S ANSI compliant database buffered logging restricted in 9 23T create with START DATABASE 1 376S description of 1 595 1 15T designating 1 10R effect on cursor behavior 1 13R decimal data type 1 13R default isolation level 1 13R escape characters 1 13R object privileges 1 12R owner naming 1 12R SQLCODE 1 14R transaction logging 1 12R transactions 1 11R FOR UPDATE not required in 1 1485 6 16T index naming 1 419S 1 484S 1 505S owner naming 1 12R privileges 1 12R procedure naming 1 495S reason for creating 1 9R Repeatable Read isolation standard in 7 13T signalled in SQLAWARN 5 12T SQL statements allowed 1 14R table privileges 1 855 11 7T using with INFORMIX SE 1 615 with BEGIN WORK 1 368 ANY keyword beginning a subquery 1 330S 3 34T in WHENEVER 1 398S use in Condition subquery 1 415S Application common features 1 18T description of 1 16T design of order entry 4 23T handling errors 5 16T performance analysis of 13 5T report generator 1 17T screen forms 1 17T Archives with INFORMIX SE 12 19T Archiving description of 1 10T 4 25T INFORMIX OnLine
25. Stored Procedure Privileges Use the EXECUTE ON option with a procedure name to grant another user the ability to run a stored procedure that you own When you create an owner privileged stored procedure the default privilege is PUBLIC SE If you create a procedure in a database that is ANSI compliant no default level privileges are granted WITH GRANT OPTION Using the WITH GRANT OPTION keyword conveys the specified privilege to user along with the right to grant those same privileges to other users You create a chain of privileges that begins with you and extends to user as well Syntax 1 237 GRANT 1 238 Syntax as to whomever user conveys the right to grant privileges If you use the WITH GRANT OPTION keyword you can no longer control the dissemination of privileges If you revoke from user the privilege that you granted using the WITH GRANT OPTION keyword you sever the chain of privileges That is when you revoke privileges from user you revoke automatically the privileges of all users who received privileges from user or from the chain that user created unless user or the users who received privileges from user were granted the same set of privileges by someone else The following examples illustrate this situation You as the owner of the table items issue the following statements to grant access to Mary REVOKE ALL ON items FROM PUBLIC GRANT SELECT UPDATE ON items TO mary WITH GRANT OPTION
26. WHERE item_num 1 AND order_num 1001 UPDATE tablel SET coll col2 col3 SELECT MIN ship_charge MAX ship_charge FROM orders 07 01 1992 WHERE col4 1001 WHERE Clause 1 388 Syntax The WHERE clause allows you to limit the rows that you want to update If you omit the WHERE clause every row in the table is updated The WHERE clause consists of a standard search condition For more information see the SELECT statement on page 1 310 The following exam ple illustrates a WHERE condition within an UPDATE statement In this UPDATE example the statement updates three columns state zipcode and phone in each row of the customer table that has a corresponding entry in a table of new addresses called new_address UPDATE customer SET state zipcode phone SELECT state zipcode phone FROM new_address WHERE new_address cust_num customer cust_num WHERE customer cust_num IN SELECT cust_num FROM new_address When you use the UPDATE statement with the WHERE clause and no rows are updated the SQLNOTFOUND value is 100 in ANSI compliant databases and 0 in databases that are not ANSI compliant If the UPDATE WHERE is a part of a multistatement prepare and no rows are returned the SQLNOT FOUND value is 100 for ANSI compliant databases and databases that are not ANSI compliant Syntax 1 389 UPDATE WHERE CURRENT OF Clause 1 390 Syntax You can use the CURRENT OF key
27. Whenever a PUT or FLUSH statement executes or the cursor closes subtract the third field of the SQLERRD array from pending At any time total minus pending is the number of rows actually inserted If all commands are successful pending contains zero after the cursor is closed If an error occurs during a PUT FLUSH or CLOSE statement the value remaining in pending is the number of uninserted discarded rows References See the CLOSE FLUSH DECLARE and OPEN statements which are cursor related in this manual Also see the ALLOCATE DESCRIPTOR statement In the Informix Guide to SQL Tutorial see the discussion of the PUT statement in Chapter 6 Syntax 1 291 RECOVER TABLE RECOVER Purpose Syntax Usage TABLE Use the RECOVER TABLE statement with INFORMIX SE to restore a database table in the event of failure SE a CRECOVER TABLE The RECOVER TABLE statement applies the table audit trail to an archive copy of the database INFORMIX SE uses audit trails to record operations on a per table basis You can issue a RECOVER TABLE statement if you own the table or have the DBA privilege on the database If a system failure occurs use an operating system utility to restore each table file for which you have an audit trail Issue the RECOVER TABLE statement to update each newly restored table with the transactions recorded in the audit trail Backup Restore Procedure 1 292 Syntax The recommended back
28. exec sql commit work oe S 38 8 S S S alance ll b b 1 J PREPARE Using Prepared Statements for Efficiency To increase performance efficiency you can use the PREPARE statement and an EXECUTE statement in a loop to eliminate overhead caused by redundant parsing and optimizing For example an UPDATE statement located within a WHILE loop is parsed each time the loop runs If you prepare the UPDATE statement outside the loop the statement is parsed only once eliminating overhead and speeding statement execution The following example shows how to prepare an INFORMIX ESQL C statement to improve performance exec sql begin declare section char disc_up 80 int cust_num exec sql end declare section main sprintf disc_up s s update customer set discount 0 1 where customer_num exec sql prepare upl from disc_up while 1 printf Enter customer number or 0 to quit scanf d cust_num if cust_num 0 break exec sql execute upl using cust_num References See the DECLARE DESCRIBE EXECUTE FREE and OPEN statements in this manual In the Informix Guide to SQL Tutorial see the discussion of PREPARE statements and dynamic SQL in Chapter 5 Syntax 1 283 PUT PUT Purpose Use the PUT statement to store a row in an insert buffer for later insertion into the database cursor PUT T a id N cursor variable
29. neg ame ES p eass Usage You must be the owner of the procedure or have the DBA privilege to use the DROP PROCEDURE statement Dropping the procedure removes the text and executable versions of the procedure Note You cannot drop a procedure from within the same procedure You cannot use a ROLLBACK WORK statement to undo a DROP PROCEDURE statement If you roll back a transaction that contains a DROP PROCEDURE statement the procedure is not re created and you do not receive an error message References See the CREATE PROCEDURE statement in this manual In the Informix Guide to SQL Tutorial see the discussion of using procedures in Chapter 14 1 176 Syntax DROP SYNONYM DROP SYNONYM Purpose Syntax Usage Use the DROP SYNONYM statement to remove a previously defined synonym Synonym aw DROP SYNONYM _ Name You must be the owner of the synonym or have the DBA privilege to use the DROP SYNONYM statement The following statement drops the synonym nj_cust owned by cathyg DROP SYNONYM cathyg nj_cust If a table is dropped any synonyms in the same database as the table that refer to the table also are dropped If a synonym refers to an external table and the table is dropped the synonym remains in place until you explicitly drop it using DROP SYNONYM You can create another table or synonym in place of the dropped table giving the new object the name of the drop
30. 1 DAY TO DAY AND INTERVAL 4 DAY TO DAY unit_price BETWEEN loprice AND hiprice IN Condition 1 408 Syntax The IN condition is satisfied when the expression to the left of the word IN is included in the list of items The NOT option produces a search condition that is satisfied when the expression is not in the list of items Null values do not satisfy the condition Condition Some IN conditions are shown in the following examples WHERE state IN CA WA OR WHERE manu_code IN HRO HSK WHERE user_id NOT IN USER WHERE order_date NOT IN TODAY The TODAY function is evaluated at execution time CURRENT is evaluated when a cursor opens or when the query executes if it is a singleton SELECT If you use the USER function note that it is case sensitive it perceives minnie and Minnie as different values IS NULL Condition The IS NULL condition is satisfied if the column contains a null value If you use the IS NOT NULL option the condition is satisfied when the column con tains a value that is not null The following example shows an IS NULL condition WHERE paid_date IS NULL LIKE and MATCHES Condition A LIKE or MATCHES condition tests for matching character strings The condition is true or satisfied when the value of the column on the left matches the pattern specified by the quoted string You can use wildcard characters in the string Null values do not satisfy the condi
31. 1 430 AND p 1 430 J Expression Literal p 1 430 IN s3 Number 2 a mh p 1 493 NOT Literal DATETIME p 1 487 Literal INTERVAL p 1 490 Quoted N String p 1 497 N topay Name L A Assen p 1 506 View CURRENT Di DATETIME name LA Field f tee Synonym P Namie LA SITENAME p 1 O F 2 DBSERVERNAME alias column ee Ss aa 4 NOT Quoted pei LIKE String Tabl Y Sem p 1 497 N name L A nor ME if p 1 506 MATCHE CHES ESCAPE char View NJ Name L A p 1 510 Synonym N Name L A p 1 504 alias 1 406 Syntax y7 Condition alias is an alias for the table that contains the column char is a single character enclosed in quotation marks column name is the name of the column Refer to the following sections for more information e Using relational operator conditions refer to Relational Operator Con ition on page 1 407 d Using the BETWEEN condition refer to BETWEEN Condition on page 1 408 e Using the IN condition refer to IN Condition on page 1 408 e Using the IS NULL condition refer to the IS NULL Condition on page 1 409 Using the LIKE and MATCHES condition refer to the LIKE and MATCHES Condition on page 1 409 Relational Operator Condition Some relational operator conditions are s
32. 114 115 72 73 74 75 76 29 30 31 116 117 118 32 119 33 34 120 121 77 78 35 1 502 Syntax Relational Operator Num Char Num Char Num Char 36 79 O 122 Zz 37 80 P 123 38 amp 81 Q 124 39 i 82 R 125 40 83 S 126 41 84 T 127 del 42 z 85 U X CTRL X Syntax 1 503 Synonym Name Synonym Name Purpose Use the Synonym Name segment wherever you see a reference to asynonym name in a syntax drawing It appears in the following statements ALTER TABLE CREATE AUDIT CREATE INDEX CREATE SYNONYM CREATE VIEW DELETE DROP AUDIT DROP SYNONYM DROP TABLE DROP VIEW GRANT INSERT LOCK TABLE RECOVER TABLE RENAME COLUMN RENAME TABLE REVOKE SELECT UNLOCK TABLE UPDATE UPDATE STATISTICS 1 504 Syntax Syntax Usage Synonym Name Identifier gt p 1 469 owner owner Me database ag a dbservername database is the name of the database in which the synonym resides dbservername is the name of the INFORMIX OnLine Dynamic Server database server that is home to database The sign is a literal character that you must use to introduce the database server name owner is the user name of the owner of the synonym If you are using an ANSI compliant database you must use the owner convention for a synonym that you do not own If you use quotes owner appears exactly as typed The actual name of the synony
33. CREATE TABLE quipement code NCHAR 6 description NVARCHAR 128 10 prix_courant MONEY 6 2 CREATE VIEW _va AS SELECT num ro nom FROM abonn s Nearly all Informix identifiers work with NLS enabled The only exception may be Connection Name depending upon your system setup Note If you receive an error message that seems unrelated to the statement that caused the error you should check to determine whether the statement uses a reserved word as an identifier The following list specifies all the ANSI reserved words If you use one of these words as an identifier you must perform the following actions e Set DBANSIWARN or use the ansi flag at compile time you receive compile time warnings Set DBANSIWARN for runtime warning flags are set in the SQLAWARN array of sqlca 1 470 Syntax ADA all and any as asc authorization avg begin between by char character check close cobol commit continue count create current cursor dec decimal declare delete desc distinct double end escape exec execute exists fetch float for fortran found from go goto group having in indicator insert int integer into is language like max min module not null numeric of on open option or Potential Ambiguities and Syntax Errors Identifier order pascal pli precision primary procedure privileges public real rollback schema section select
34. CREATE TRIGGER Then in the cascading triggers shown in the following example trig2 fails at run time because it references column b which is updated by the triggering UPDATE statement See Cascading Triggers on page 1 130 for more information about cascading triggers CREATE TRIGGER trigl UPDATE OF a ON tabl lt Valid AFTER UPDATE tab2 set e e 1 CREATE TRIGGER trig2 UPDATE of e ON tab2 Invalid AFTER UPDATE tabl set b b 1 Rules for Stored Procedures The following rules apply to a stored procedure that is used as a triggered action The stored procedure cannot be a cursory procedure that is a procedure that returns more than one row in a place where only one row is expected When an EXECUTE PROCEDURE statement is the triggered action you can specify the INTO clause only for an UPDATE trigger when the triggered action occurs in the FOR EACH ROW section In this case the INTO clause can contain only column names from the triggering table The following statement illustrates the appropriate use of the INTO clause CREATE TRIGGER upd_totpr UPDATE OF quantity ON items REFERENCING OLD AS pre_upd NEW AS post_upd FOR EACH ROW EXECUTE PROCEDURE calc_totpr pre_upd quantity post_upd quantity pre_upd total_price INTO total_price When the INTO clause appears in the EXECUTE PROCEDURE statement the database server updates the columns named there with the values return
35. DELETE ON stock REFERENCING OLD AS pre_del FOR EACH ROW DELETE FROM items WHERE manu_code pre_del manu_code CREATE TRIGGER del_items DELETE ON items REFERENCING OLD AS pre_del FOR EACH ROW EXECUTE PROCEDURE log_order pre_del order_num When you are not using logging or you are using the INFORMIX SE database server with or without logging referential integrity constraints on both the manufact and stock tables would prohibit the triggers in this example from executing When you use INFORMIX OnLine Dynamic Server with logging CREATE TRIGGER however the triggers execute successfully because constraint checking is deferred until all the triggered actions are complete including the actions of cascading triggers See Constraint Checking on page 1 131 for more infor mation about how constraints are handled when triggers execute The database server prevents loops of cascading triggers by not allowing you to modify the triggering table in any cascading triggered action except an UPDATE statement which does not modify any column updated by the triggering UPDATE statement Constraint Checking When you use logging INFORMIX OnLine Dynamic Server defers constraint checking on the triggering statement until after the statements in the trig gered action list execute OnLine effectively executes a SET CONSTRAINTS ALL DEFERRED statement before executing the triggering statement After
36. INFORMIX ESQL C and INFORMIX ESQL COBOL respectively In each example the first line shows an embedded variable name and the second line shows a quoted string that identifies the allocated system descriptor area exec sql deallocate descriptor descname exec sql deallocate descriptor descl INFORMIX ESQL C EXEC SQL DEALLOCATE DESCRIPTOR DESCNAME END EXEC EXEC SQL DEALLOCATE DESCRIPTOR DESC1 END EXEC INFORMIX ESQL COBOL References 1 144 Syntax See the ALLOCATE DESCRIPTOR DECLARE DESCRIBE EXECUTE FETCH GET DESCRIPTOR OPEN PREPARE PUT and SET DESCRIPTOR statements in this manual In the Informix Guide to SQL Tutorial see the discussion of dynamic SQL in Chapter 5 DECLARE DECLARE Purpose Use the DECLARE statement to define a cursor that represents the active set of rows specified by a SELECT INSERT or EXECUTE PROCEDURE statement Syntax INSERT cursor Statement ST DECLARE id CURSOR FOR Subset p 1 157 WITH _ SELECT 3 cursor HOLD N Statement FOR variable Subset UPDATE p 1 152 3 SCROLL 5 CURSOR FORSY m OF column WITH SELECT HOLD N Statement A p 1 310 Ko statement id statement id A variable EXECUTE procEbure LY Statement p 1 192 column is a column that you can update through the cursor cursor id is the identifier of the cursor in ot
37. TRUNC 24536 8746 2 24500 TRUNC 24536 8746 0 24536 TRUNC 24536 8746 2 24536 87 2 0 2 TRUNC function If you use a MONEY data type as the argument for the TRUNC function and you truncate to zero places the 00 places are removed For example the fol lowing SELECT statement truncates a MONEY value and an INTEGER value It displays 125 and a truncated price in integer format for each row in items SELECT TRUNC 125 46 TRUNC total_price FROM items DBINFO Function 1 448 Syntax Use the DBINFO function for any of the following purposes To locate the name of a dbspace corresponding to a tblspace number or expression e To find out the last serial value inserted in a table e To find out the number of rows processed by selects inserts deletes updates and execute procedure statements Expression The DBINFO function can be used anywhere within SQL statements and within stored procedures DBINFO Function p gt DBINFO ROME DBSPACE tblspace num Ne expression 2 sqica sqlerrd1 sqica sqlerrd2 P tblspace num The tblspace partition number of a table expression An expression that evaluates to tblspace num The expression can contain procedure variables host variables column names or subqueries Using the DBSPACE Option The DBSPACE option returns a character string that contains the name of the dbspace corresponding to a tblspace number
38. You must supply an additional parameter either tblspace num or an expression that evaluates to tblspace num The following example uses the DBSPACE option First it queries the systa bles system catalog table to determine the tblspace num for the table customer then it executes the function to determine the dbspace name SELECT tabname partnum FROM systables If the statement returns a partition number of 16777289 you insert that value into the second argument to find which dbspace contains the customer table SELECT DBINFO DBSPACE 16777289 FROM systables Using the sqlca sqlerrd1 Option The sqlca sqlerrd1 option returns a single integer that provides the last serial value inserted into a table You can use this DBINFO function to retrieve the last serial value inserted into a table or to determine the number of rows pro cessed by a query anywhere within SQL statements and within stored procedures Syntax 1 449 Expression 1 450 Syntax This option applies to all SQL APIs To ensure valid results use this option immediately following an INSERT statement that inserts a serial value The following example uses the sqlca sqlerrd1 option EXEC SQL create table fst_tab ordernum serial partnum int EXEC SQL create table sec_tab ordernum serial EXEC SQL insert into fst_tab values 0 1 EXEC SQL insert into fst_tab values 0 4 EXEC SQL insert into fst_tab values 0 6
39. because it appears as the argument of an aggregate function The COUNT and SUM keywords are applied to each group not the whole query set SELECT order_num COUNT SUM total_price FROM items GROUP BY order_num If a column stands alone in a column expression in the select list you must use it in the GROUP BY clause If a column is combined with another column by an arithmetic operator you can choose to group by the individual columns or by the combined expression using a specific number Using Select Numbers You can use one or more integers in the GROUP BY clause to stand for column expressions In the following example the first SELECT statement uses select numbers for order_date and paid_date order_date in the GROUP BY clause Note that you can group only by a combined expression using the select number notation In the second SELECT statement you cannot replace the 2 with the expression paid_date order_date SELECT order_date COUNT paid_date order_date FROM orders GROUP BY 1 3 SELECT order_date paid_date order_date FROM orders GROUP BY order_date 2 Nulls in the GROUP BY Clause Each row that contains a null value in a column specified by a GROUP BY clause belongs to a single group that is all null values are grouped together Syntax 1 335 SELECT HAVING Clause 1 336 Syntax Use the HAVING clause to apply one or more qualifying conditions to groups
40. column is placed new column name is the name of the column that you are adding For additional information about column naming see Identifier on page 1 469 Use the ADD clause to add a column to a table You cannot add a SERIAL column to a table if the table has data in it Syntax 1 17 ALTER TABLE DEFAULT Clause DEFAULT Clause DEFAULT literal ana N NULL A CURRENT M4 p 1 440 A U DATETIME pa Field Qualifier p 1 428 USER p 1 438 EE K SITENAME p 1 438 DBSERVERNAME J p 1 438 literal represents a literal default of the appropriate type for the 1 18 Syntax column The default value is inserted into the column when an explicit value is not specified When a default is not specified and the column allows nulls the default is NULL When you designate NULL as the default value for a column you cannot use the keywords NOT NULL as part of the column definition You cannot place a default on SERIAL columns When the altered table already has rows in it the new column contains the default value for all existing rows You can designate literal terms as default values Use a literal term to define alpha or numeric constant characters To use a literal term as a default value follow these rules ALTER TABLE Use the Literal INTEGER DECIMAL CHARACTER INTERVAL DATETIME With Colu
41. compiled products return error status information on the first error in the multistatement text No indication exists of which statement in the sequence causes an error You can use sqlca to find the offset of the following errors In ESQL C sqlerrd 4 In ESQL COBOL SQLERRD 5 For additional information about sqlca and error status information see your SQL API manual In a multistatement prepare if no rows are returned from a WHERE clause in the following statements you get SQLNOTFOUND 100 in both ANSI compliant databases and databases that are not ANSI compliant UPDATE WHERE SELECT INTO TEMP WHERE INSERT INTO WHERE DELETE FROM WHERE In the following example six SQL statements are prepared into a single INFORMIX ESQL C string query Individual statements are delimited with semicolons A single exec sql prepare statement can prepare all six state ments for execution and a single exec sql execute statement can execute the qid string exec sql begin work sprintf query sS S S begin work update account set balance balance where acct_number update teller set balance where teller_number 7 update branch set balance balance where branch_number insert into history values exec sql prepare qid from query exec sql execute qid using delta acct_number delta teller_number delta branch_number timestamp values
42. e For information on using a literal INTERVAL see Literal INTERVAL as an Expression on page 1 441 e For more information on using a literal DATETIME see Literal DATETIME as an Expression on page 1 441 You cannot designate NULL as a default value for a column that is part of a primary key Data Type Requirements for Certain Columns The following table indicates the data type requirements for columns that specify the CURRENT USER TODAY SITENAME or DBSERVERNAME functions as the default value Function Name Data Type Requirement CURRENT DATETIME column with matching qualifier DBSERVERNAME CHAR NCHAR NVARCHAR or VARCHAR column at least 18 characters long inclusive SITENAME CHAR NCHAR NVARCHAR or VARCHAR column at least 18 characters long inclusive TODAY DATE column USER CHAR or VARCHAR column at least 8 characters long Syntax 1 89 CREATE TABLE The next example creates a table called accounts In accounts the acc_type and acc_descr columns have literal default values and acc_id defaults to the user s login name CREATE TABLE accounts acc_num INTEGER DEFAULT 0001 acc_type CHAR 1 DEFAULT A acc_descr CHAR 20 DEFAULT New Account acc_id CHAR 8 DEFAULT USER Specifying NOT NULL in a Column Definition If you do not indicate a default value for a column the default is null unless you include the NOT NULL keywords after the data type of the column In this
43. expression lists in the same FOR statement The following example shows a mixture using an integer variable Values in the expression list include the value returned from a SELECT statement a sum of an integer variable and a constant the values returned from a procedure named p_get_int and integer constants CREATE PROCEDURE for_ex DEFINE i j INT LET j 10 FOR i I 1 TO 20 SELECT cl FROM tab WHERE id 1 3 20 to 3 20 p_get_int 99 98 90 to 80 step 2 INSERT INTO tab VALUES i END FOR END PROCEDURE SPL Statements 2 19 FOREACH FOREACH Purpose Use a FOREACH loop to select and manipulate more than one row Syntax FOREACH a ae WITH HOLD Bg cursor name ne Ti WITH HOLD C EXECUTE PROCEDURE 7 Procedure FOR S SELECT INTO Statement p 2 22 Statement Block p 1 72 END FOREACH Name p 1 495 cursor name variable name 2 20 SPL Statements J Di INTO variable name xa J T variable _ ZE oe name SELECT INTO statement Expression Subset p 2 23 is an identifier that you supply as a name for the is the name of a procedure variable Procedure arguments are bound to procedure parameters by name or position but not both That is you can use variable name syntax for none or all the arguments specified in one FOREACH EXECUTE PROCEDURE statement U
44. on page 1 276 in a text that contains multiple statements separated by semicolons CLOSE DATABASE DATABASE SELECT CREATE DATABASE DROP DATABASE START DATABASE Thus a SELECT statement is not allowed in a multistatement prepare the statements that could cause the current database to be closed in the middle of executing the sequence of statements are also not allowed For general infor mation about multistatement prepares see Preparing Sequences of Multiple SQL Statements on page 1 281 Syntax 1 277 PREPARE Preparing Statements When Parameters Are Known In some prepared statements all needed information is known at the time the statement is prepared Here is an example in INFORMIX ESQL C in which two statements are prepared from constant data sprintf redo_st s s drop table worktl create table worktl wtk serial wtv float exec sql prepare redotab from redo_st Preparing two statements from constant data in INFORMIX ESQL C For further information consult the manual for your application development tool Preparing Statements That Receive Parameters At Execution 1 278 Syntax In some statements parameters are unknown when the statement is prepared because a different value can be inserted each time the statement is executed In these statements you can use a question mark placeholder where a parameter must be supplied when the statement is executed The PREPARE statements in th
45. the function The following statement executes a function called error_recovery if the program detects an error condition WHENEVER SQLERROR CALL error_recovery You cannot specify the name of a stored procedure with the CALL keyword If you want to call a stored procedure use the CALL clause to execute a function that contains the EXECUTE PROCEDURE statement Syntax 1 401 WHENEVER CONTINUE Keyword Use the CONTINUE keyword to instruct the program to take no action You can use this keyword to turn off a previously specified option STOP Keyword Use the STOP keyword to exit from the program immediately The following statement stops program execution each time the database server issues a warning WH ENEVER SQLWARNING STOP PERFORM Keyword for COBOL Use the PERFORM keyword to execute a paragraph of COBOL code The following example executes the COBOL paragraph ERR CHK when an error is encountered EX EC SQL WHEN EVER ERROR PERFORM ERR CHK END EXEC References See the EXECUTE PROCEDURE and FETCH statements in this manual See the chapter on error checking in your SQL API product manual 1 402 Syntax Segments Segments Segments are the elements of syntax that are extracted from the syntax diagrams and discussed separately for clarification and ease of use The following segments which are common to more than one statement are gathered in the foll
46. user appears exactly as typed MEE In an ANSI compliant database if you do not use quotes around user the name of the user is stored in uppercase letters Usage You can use the REVOKE statement with the GRANT statement to finely control the ability of users to modify the database as well as access and modify data in the tables 1 300 Syntax REVOKE You can revoke all or some of the privileges that you granted to other users No one can revoke privileges granted by another user However if you revoke from user the privileges that you granted using the WITH GRANT OPTION keywords you sever the chain of privileges granted by that user In this case when you revoke privileges from user you automatically revoke the privileges of all users who received privileges from user or from the chain that user created If you revoke the EXECUTE privilege on a stored procedure from a user that user can no longer run that procedure using either the EXECUTE PROCEDURE or CALL statements Users cannot revoke privileges from themselves You cannot use a ROLLBACK WORK statement to undo a REVOKE statement that successfully executes If you roll back a transaction that contains a REVOKE statement the privilege is not granted again to the user and you do not receive an error message Table Level Privileges Table Level Privileges gt a ALL oe p PRIVILEGES To revoke a table level privilege from a user you must revok
47. variable name is a user defined procedure call and not an SQL function or a system function call For example the following statement defines length as a procedure not the SQL LENGTH function This disables the SQL LENGTH function within the scope of the statement block You would use such a definition if you had cre ated a procedure with the name length prior to defining and using it in another procedure as shown in the following example EFINE length PROCEDURE LET x length a b c If you create a procedure named the same as an aggregate function SUM MAX MIN AVG COUNT or one named extend you must qualify the proce dure name with the owner name Declaring Variables for BYTE and TEXT Data The keyword REFERENCES indicates that variable name is not a BYTE or TEXT value but rather a pointer to the BYTE or TEXT value You use the variable as though it holds the data The following example defines a local BYTE variable CREATE PROCEDURE use_blob DEFINE i INT DEFINE 1_blob REFERENCES BYTE END PROCEDURE use_blob If you pass a variable of type TEXT or BYTE to a procedure the data is passed to the database server and stored in the root dbspace or DBSPACETEMP if set You do not need to know the location or name of the file that holds the data only the name of the BYTE or TEXT variable as it is defined in the procedure is needed for BYTE or TEXT manipulation SPL Statements 2
48. 1 200 Syntax You can use a system descriptor area as an output variable The keywords USING SQL DESCRIPTOR introduce the name of the system descriptor area into which you fetch the contents of a row The values returned by the FETCH statement can then be transferred from the system descriptor area into host variables by using the GET DESCRIPTOR statement For more information see your INFORMIX ESQL manual The following examples show sample FETCH USING SQL DESCRIPTOR statement in INFORMIX ESQL C and INFORMIX ESQL COBOL respectively exec sql fetch selcurs using sql descriptor desc INFORMIX ESQL C EXEC SQL FETCH SEL_CURS USING SQL DESCRIPTOR DESC END EXEC INFORMIX ESQL COBOL FETCH Using an sqlda Structure Z You can supply destinations using a pointer to an sqlda structure This structure contains data descriptors each one specifying the data type and memory location for one selected value For more information see the INFORMIX ESQL C Programmer s Manual The keywords USING DESCRIPTOR introduce the name of the sqlda pointer structure When you create a SELECT statement dynamically you cannot use an INTO host variable clause because you cannot name host variables in a prepared statement If you are certain of the number and type of values in the select list you can use an INTO host variable clause in the FETCH statement How ever if the query was generated by user input you might not be cert
49. 1 5R 7 6T scope of lock 7 6T setting lock mode 7 13T shared locks 1 6R types of locks database lock 7 6T exclusive lock 7 6T key lock 7 8T page lock 1 108S 7 8T promotable lock 7 6T 7 9T row lock 1 108S 7 8T shared lock 7 6T table lock 7 7T update cursors effect on 1 152S update locks 1 385S waiting period 1 370S with DELETE 6 4T FETCH 1 201S scroll cursor 1 369S SET ISOLATION 1 366S SET LOCK MODE 1 370S UNLOCK TABLE 1 381S update cursor 7 9T within transaction 1 35S See also Table locking LOG IN keywords syntax in CREATE DATABASE 1 575 LOG10 function syntax in expression 1 452S use in expression 1 4525 Logarithmic function syntax LOG10 function 1 451S LOGN function 1 451S use LOG10 function 1 452S LOGN function 1 452S Loggin buffered 9 22T buffered vs unbuffered 1 372S cascading deletes 1 245 1 985 changing mode with SET LOG 1 372S choosing for OnLine database server 9 22T choosing for SE database server 9 23T finding log file location 1 60S renaming log 1 377S setting with CREATE TABLE 1 104S starting with START DATABASE 1 605 1 376S stopping 1 377S stopping with START DATABASE 1 376S unbuffered 9 22T with INFORMIX OnLine 1 595 with INFORMIX SE 1 60S with triggers 1 1345 Logical log definition of 4 25T Logical operator AND 2 36T in Condition segment 1 417S NOT 2 36T Index 27 28 Index OR 2 36T LOGN function syntax in expression 1 4525 use in expression 1 452S lok extension 1 37
50. 23T specifying ANSI compliance 1 11R specifying transactions 4 24T syntax in CREATE DATABASE 1 57S in START DATABASE 1 376S use in CREATE DATABASE 1 60S in START DATABASE 1 377S Model See Data model MODIFY keyword syntax in ALTER TABLE 1 15S use in ALTER TABLE 1 278 MODIFY NEXT SIZE keywords syntax in ALTER TABLE 1 15S use in ALTER TABLE 1 335 MONEY data type 9 12T changing data types 3 23R description of 3 16R 9 10T display format 9 12T in INSERT 4 8T syntax 1 425S using as default value 1 195 1 89S See also DECIMAL data type MONEY value setting DBMONEY environment variable 4 20R setting LC_MONETARY environment variable 4 52R specifying European format with DBMONEY 4 20R specifying for NLS 4 53R Money representing with NLS 1 15R MONTH function as time function 2 56T syntax in expression 1 454S use in expression 1 456S MONTH keyword syntax in DATETIME data type 1 4285 in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 13R 1 491S Multiple triggers column numbers in 1 115S example 1 1145 order of execution 1 115S preventing overriding 1 132S Multiple table join 2 77T Multi row query destination of returned values 1 198S managing with FETCH 1 195S N Naming convention column 1 875 1 102S 1 294S database 1 422S index 1 419S 1 484S 1 505S table 1 84S 1 470S 1 507S See also Database Name segment See also Index Name segment See also Table Name s
51. 254 MESSAGE _ LENGTH Integer Numeric int PIC 9 4 value COMP 5 SERVER_NAME Character String char 254 PIC X 254 CONNECTION_NAME Character String char 254 PIC X 254 The application specifies the exception by number using either an unsigned integer or an integer host variable an exact numeric with a scale of 0 An exception with a value of 1 corresponds to the SQLSTATE value set by the most recent SQL statement other than GET DIAGNOSTICS The association between other exception numbers and other exceptions raised by that SQL statement is undefined Thus no set order exists in which the diagnostic area can be filled with exception values Note If an error occurs within the GET DIAGNOSTICS statement that is if an 7illegal exception number is requested then the Informix internal SQLCODE and SQLSTATE variables is set to the value of that exception In addition the GET DIAGNOSTICS fields are undefined GET DIAGNOSTICS Using the RETURNED_SOLSTATE Keyword Use the RETURNED_SQLSTATE keyword to determine the SOLSTATE value that describes the exception Using the CLASS_ORIGIN Keyword Use the CLASS_ORIGIN keyword to retrieve the class portion of the RETURNED SQLSTATE value If the ISO international standard defines the class the value of CLASS_ORIGIN is equal to ISO 9075 Otherwise the value of CLASS_ORIGIN is defined by Informix and cannot be ISO 9075 Using the SUBCLASS_ORIGIN Keyword Use
52. 28T Redundant data introduced for performance 10 31T Redundant relationship 8 29T REFERENCES FOR keywords in INFO statement 1 243S REFERENCES keyword in ALTER TABLE 1 215 in CREATE TABLE 1 948 1 96S syntax in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S References privilege definition of 1 236S displaying with the INFO statement 1 243S REFERENCING clause DELETE REFERENCING clause 1 119S INSERT REFERENCING clause 1 118S UPDATE REFERENCING clause 1 120S Index 35 using referencing 1 1255 15 9T Referential constraint and a DELETE trigger 1 1125 data type restrictions 1 965 definition of 1 215 1 945 4 19T dropping 1 32S enforcing 1 86S modifying a column with 1 285 rules of use 1 945 Referential integrity 4 19T defining primary and foreign keys 8 24T Regular expression effect on performance 13 32T evaluating with NLS 1 15R Relational calculus See also relational model Relational database defined 1 11T Relational model attribute 8 14T denormalizing 10 26T description of 1 11T 8 3T to 8 33T entity 8 4T join 2 8T many to many relationship 8 11T normalizing data 8 29T one to many relationship 8 11T one to one relationship 8 11T projection 2 6T resolving relationships 8 26T rules for defining tables rows and columns 8 20T selection 2 5T Relational operation 2 5T Relational operator BETWEEN 2 32T equals 2 30T EXISTS 3 33T IN 3 33T in a WHERE clause 2 29T to 2 45T in Conditi
53. 5 16T program variable 5 5T STATUS variable 5 11T terminates on errors 5 36T 6 14T timing operations in 13 6T using SQLCODE with 5 11T WHENEVER ERROR statement 5 36T INFORMIXC environment variable 4 31R INFORMIXCOB environment variable 4 32R INFORMIXCOBDIR environment variable 4 32R INFORMIXCOBSTORE environment variable 4 33R INFORMIXCOBTYPE environment variable 4 33R INFORMIXCONRETRY environment variable 4 34R INFORMIXCONTIME environment variable 4 34R INFORMIXDIR environment variable 4 36R 12 14T INFORMIX OnLine disk access by 13 17T INFORMIX OnLine Dynamic Server allows views on external tables 11 23T and triggering statement 1 112S archiving 4 26T characteristics of 1 10T creating demonstration database Intro 10R Intro 13S disk page size 13 16T disk storage methods 10 3T to 10 12T is NLS ready 1 15R optimizer input with 13 9T signalled in SQLAWARN 5 12T when tables are locked 7 7T INFORMIX OnLine Optical 12 6T list of statements 1 7S INFORMIX SE characteristics of 1 10T creating database 9 23T creating demonstration database Intro 10R Intro 13S is NLS ready 1 15R INFORMIXSERVER environment variable 4 36R 1 46S 12 14T INFORMIXSHMBASE environment variable 4 37R INFORMIX SQL Index 23 24 Index creating database with 5 34T 9 26T UNLOAD statement 9 27T INFORMIXSTACKSIZE environment variable 4 38R INFORMIXTERM environment variable 4 38R informix rc file 4 4R Inser
54. 5R SHARE keyword syntax in LOCK TABLE 1 260S Shared memory network connection 12 7T Shared memory parameters specifying file with ONCONFIG 4 39R Shell setting environment variables in a file 4 4R specifying with DBREMOTECMD 4 25R Simple assignment 2 288 SIN function syntax in expression 1 458S use in expression 1 459S Single precision floating point number storage of 3 12R Singleton SELECT statement 1 3185 2 29T Site network 12 4T primary 12 20T secondary 12 20T SITENAME function returns servername 1 438S syntax in expression 1 436S in INSERT 1 250S use in ALTER TABLE 1 18S in CREATE TABLE 1 888 in expression 1 438S in INSERT 1 252S in SELECT 2 63T 2 65T 3 20T Slash arithmetic operator 1 4315 SMALLFLOAT data type changing data types 3 23R 40 Index description of 3 20R 9 9T syntax 1 425S SMALLINT data type changing data types 3 23R description of 3 20R 9 7T syntax 1 425S using as default value 1 195 1 89S SOME keyword beginning a subquery 1 330S 3 33T use in Condition subquery 1 415S Sort merge join 13 27T Sorting avoiding nonsequential access 13 37T avoiding with temporary table 13 36T effect on performance 13 33T in a combined query 1 344S in SELECT 1 337S nested 2 15T optimizer estimates cost 13 12T PSORT_DBTEMP environment variable 4 40R PSORT_NPROCS environment variable 4 41R sort merge join 13 27T time costs of 13 15T when there are multiple active NLS locales 1 20R
55. 8T next extent doubles 10 10T sizes of 10 8T upper limit on 10 10T EXTENT SIZE keywords 1 107S 10 8T F FETCH statement ABSOLUTE keyword 5 23T as affected by CLOSE 1 395 checking results with SQLCA 1 202S description of 5 21T fetching a row for update 1 201S locking for update 1 201S relation to GET DESCRIPTOR 1 210S sequential 5 23T specifying a value s memory location 1 198S syntax 1 194S with concatenation operator 1 432S INTO keyword 1 319S program arrays 1 199S scroll cursor 1 196S sequential cursor 1 195S 5 25T X Open mode 1 195S Field qualifier for DATETIME 3 8R 1 428S for INTERVAL 3 13R 1 4855 1 491S File compared to database 1 3T environment configuration 4 4R environment configuration checking with chkenv 5 4R extension lok 1 370S mapping and COLLCHAR 4 45R mapping and crtcmap utility 5 5R mapping and DBAPICODE 4 47R mapping format for 5 6R Index 19 20 Index permissions in UNIX 11 4T sending output with the OUTPUT statement 1 271S shell 4 4R temporary for OnLine 4 26R temporary for SE 4 27R FILE statement character position form 5 28R delimiter form 5 24R syntax for character position form 5 29R syntax for delimiter form 5 25R with dbload 5 23R Filter expression effect on performance 13 23T 13 32T 13 33T evaluated from index 13 10T 13 31T optimizer uses 13 10T 13 23T selectivity estimates 13 30T finding location of row 1 435S FIRST keyword syntax in FETCH 1 1945 use in FETCH
56. ALL ANY SOME section on page 1 415 The following example of an IN subquery finds the order numbers for orders that do not include baseball gloves stock_num 1 WHERE order_num NOT IN SELECT order_num FROM items WHERE stock_num 1 Because the IN subquery tests for the presence of rows duplicate rows in the subquery results do not affect the results of the main query Therefore put ting the UNIQUE or DISTINCT keyword into the subquery has no effect on the query results although eliminating testing duplicates can reduce the time needed for running the query EXISTS Subquery 1 414 Syntax EXISTS Subquery Condition gt EXISTS J _ with ne J Subquery NOT p 1 413 An EXISTS subquery condition evaluates to true if the subquery returns a row With an EXISTS subquery one or more columns can be returned The sub query always contains a reference to a column of the table in the main query If you use an aggregate function in an EXISTS subquery at least one row is always returned Condition The following example of a SELECT statement with an EXISTS subquery returns the stock number and manufacturer code for every item that has never been ordered and is therefore not listed in the items table It is appro priate to use an EXISTS subquery in this SELECT statement because you use the subquery to test both stock_num and manu_code in items SELECT stock_num m
57. ALTER TABLE customer ADD CONSTRAINT UNIQUE lname fname CONSTRAINT u_cust When you do not provide a constraint name the database server provides one You can find the name of the constraint in the sysconstraints system cat alog table See Chapter 2 of the Informix Guide to SQL Reference for more information about the sysconstraints system catalog table Adding a Unique Constraint The following rules apply when you add a unique constraint The columns can contain only unique values e When you place a unique constraint on a column or set of columns and a unique index already exists on that column or set of columns the con straint shares the index However if the existing index allows duplicates the database server returns an error You must then drop the existing index before adding the unique constraint e An existing unique constraint cannot have the same name as the constraint you are adding A composite list can include no more than 16 column names The total length of all the columns cannot exceed 255 bytes A composite list can include no more than 8 column names and the total 1 30 Syntax length of all the columns cannot exceed 120 bytes ALTER TABLE Adding a Unique or Primary Key Constraint The following rules apply when you add a unique or primary key constraint When you place a unique or primary key constraint on a column or set of columns and a unique index already exists on that column or se
58. CHECK OPTION 1 138S with CREATE SCHEMA 1 77S with SELECT notation 1 136S Creating a database from ASCII files 5 14R a dbload command file 5 23R crtcmap utility creating mapping files 5 5R description of 5 5R error messages for 5 7R formats for mapping files 5 6R Currency representing with NLS 1 15R Current database specifying with DATABASE 1 140S CURRENT function 4GL example 13 6T comparing column values 2 56T syntax in Condition segment 1 405S in expression 1 436S in INSERT 1 250S use in ALTER TABLE 1 18S in CREATE TABLE 1 888 in expression 1 440S in INSERT 1 252S in WHERE condition 1 441S input for DAY function 1 441S CURRENT keyword DISCONNECT statement 1 168S syntax in FETCH 1 1945 use in FETCH 1 196S CURRENT OF keywords syntax in DELETE 1 159S in UPDATE 1 383S use in DELETE 1 161S in UPDATE 1 390S Cursor activating with OPEN 1 263S active set of 5 24T affected by transaction end 1 40S 10 Index associating with prepared statements 1 154S characteristics 1 149S closing 1 388 7 18T closing with ROLLBACK WORK 1 307S declaring 1 145S 5 20T definition of types 1 148S for insert 6 8T for update 6 15T 7 9T hold 7 18T manipulation statements 1 6S opening 1 264S 1 265S 5 20T 5 24T retrieving values with FETCH 1 194S 5 21T scroll 1 149S 5 23T sequential 1 149S 5 23T 5 25T statement as trigger event 1 112S using with transactions 1 155S with DELETE 1 159S INTO keyword in SELECT 1 319S prepared state
59. CREATE SCHEMA You can grant privileges only using the CREATE SCHEMA statement you cannot revoke or drop privileges Creating Objects or Granting Privileges Outside CREATE SCHEMA 1 78 Syntax If you create an object or use the GRANT statement outside a CREATE SCHEMA statement you receive warnings if you use the ansi flag or set DBANSIWARN CREATE SCHEMA References See the CREATE TABLE CREATE INDEX CREATE VIEW CREATE SYNONYM and GRANT statements in this manual In the Informix Guide to SQL Tutorial see the discussion of creating the database in Chapter 9 Syntax 1 79 CREATE SYNONYM CREATE SYNONYM Purpose Syntax _ Synonym Table Name Ma CREATE SYNONYM 9x70 y FOR 7 gt 1 506 Usage 1 80 Syntax Use the CREATE SYNONYM statement to provide an alternative name for a table or view p 1 504 PUBLIC View Name p 1 510 PRIVATE Users have the same privileges for a synonym that were granted to them on the table to which the synonym applies The synonym name must be unique that is the synonym name cannot be the same as another database object such as a table view or temporary table Once created a synonym persists until the owner of the synonym executes the DROP SYNONYM statement This property distinguishes a synonym from an alias that you can use in the FROM clause of a SELECT statement The alias persists only for the lifetime of the SEL
60. CREATE TABLE customer lname CHAR 15 2 On the database server called accntg CREATE SYNONYM cust FOR stores6 training customer 3 On the database server called zoo CREATE TABLE customer lname CHAR 15 4 On the database server called training DROP TABLE customer CREATE SYNONYM customer FOR stores6 zoo customer The synonym cust on the acentg database server now points to the customer table on the zoo database server The following steps show an example of chaining two synonyms together and changing the table to which a synonym points 1 On the database server called training CREATE TABLE customer lname CHAR 15 2 On the database server called acentg CREATE SYNONYM cust FOR stores6 training customer 3 On the database server called training DROP TABLE customer CREATE TABLE customer lastname CHAR 20 The synonym cust on the accntng database server now points to a new version of the customer table on the training database server References See the DROP SYNONYM statement in this manual In the Informix Guide to SQL Tutorial see the discussion of synonyms in Chapter 5 and Chapter 12 Syntax 1 83 CREATE TABLE CREATE TABLE Purpose Syntax CREATE TABLE Use the CREATE TABLE statement to create a new table in the current database place data integrity constraints on its columns or on a combination of its columns designate the size of its initial and subsequent ext
61. Chapter 9 and extent sizing in Chapter 10 Syntax 1 109 CREATE TRIGGER CREATE TRIGGER Purpose Use the CREATE TRIGGER statement to create a trigger on a table in the database A trigger is a database object that automatically sets off a specified set of SOL statements when a specified event occurs Syntax DB EZA CREATE TRIGGER Trigger Name p 1 113 Tabl ear Nama p 1 506 Tabl N DELETE ON Namo p 1 506 UPDATE Table Y Clause ON Name p 1 114 p 1 506 1 110 Syntax Action Clause p 1 116 Insert Action REFERENCING Clause Clause Referencing p 1 118 p 1 121 Action Clause 1 116 Delete Action REFERENCING Clause Clause Referencing p 1 119 p 1 121 Clause epee REFERENCING p 1 120 Action Clause Referencing p 1 121 Usage E C E CO CREATE TRIGGER You must be either the owner of the table or have database administrator DBA status to create a trigger on a table You can define a trigger with a stand alone CREATE TRIGGER statement You can define a trigger as part of a schema by placing the CREATE TRIGGER statement inside a CREATE SCHEMA statement You can create a trigger only on a table in the current database You cannot create a trigger on a temporary table a view or a system catalog table You cannot create a trigger i
62. DATABASE statement to assign a log file to an exist ing INFORMIX SE database or to assign a new log file with a different name You can determine the location of the log file for the current database by running the following SELECT statement SELECT dirpath FROM informix systables WHERE tabtype L 1 60 Syntax CREATE DATABASE Designating an ANSI Compliant INFORMIX SE Database The following example creates an ANSI compliant database CREATE DATABASE employees WITH LOG IN u acctg lfile MODE ANSI References See the CLOSE DATABASE CONNECT TO DATABASE DROP DATABASE and START DATABASE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of creating a database in Chapter 9 Syntax 1 61 CREATE INDEX CREATE INDEX Purpose Use the CREATE INDEX statement to create an index for one or more columns in a table and optionally to cluster the physical table in the order of the index When more than one column is listed the concatenation of the set of columns is treated as a single composite column for indexing 1 62 Syntax CREATE INDEX Syntax ind CREATE INDEX namo ON Clause p 1 484 UNIQUE CLUSTER DISTINCT FILLFACTOR percent Usage ON g Clause C Table Bp ON Name column name p p 1 506 ASC Synonym Name DESC p 1 504 temporary table name column name is th
63. Dynamic Server methods 4 26T transaction log 4 26T ARC_DEFAULT environment variable 4 14R ARC_KEYPAD environment variable 4 14R Arithmetic functions See Algebraic functions Arithmetic operator in expression 1 4315 2 46T Array moving rows into with FETCH 1 199S AS keyword in SELECT 1 312S syntax in CREATE VIEW 1 136S in GRANT 1 231S use in CREATE VIEW 1 137S in GRANT 1 239S with display labels 1 316S with table aliases 1 325S ASC keyword syntax in CREATE INDEX 1 638 in SELECT 1 337S use in CREATE INDEX 1 668 in SELECT 1 338S Index 3 4 Index Ascending order in SELECT 2 14T ASCII collating order 1 15R 1 501S ASIN function syntax in expression 1 458S use in expression 1 460S Asterisk wild card character in SELECT 2 12T Asterisk arithmetic operator 1 431S use in SELECT 1 312S At sign in database name 1 421S ATAN function syntax in expression 1 458S use in expression 1 460S ATAN2 function syntax in expression 1 458S use in expression 1 461S Attribute identifying 8 14T important qualities of 8 15T nondecomposable 8 15T Audit trail applying with RECOVER TABLE 292S dropping with DROP AUDIT 1 171S manipulating audit trail file 1 293S no clustered index 1 64S starting with CREATE AUDIT 1 558 Automatic type conversion See Data type conversion AVG function as aggregate function 2 53T syntax in expression 1 462S use in expression 1 464S B Bachman C R 8 17T Backslash a
64. Each connection encompasses a set of information that is called the connection context The connection context includes the name of the current user and all the information that the database environment associates with this name The connection context is saved when an application becomes dormant and it is restored when the application becomes current again Syntax 1 45 CONNECT The DEFAULT Option If you specify the DEFAULT option a connection is made to a default database server This form of the CONNECT statement does not open a data base The default database server can be either an INFORMIX OnLine Dynamic Server or a INFORMIX SE database server and it can be either local or remote You designate the default database server by setting its name in the environment variable INFORMIXSERVER If you select the DEFAULT option for the CONNECT statement you must use the DATABASE statement the CREATE DATABASE statement or the START DATABASE statement to open or create a database in the default database environment The Implicit Connection with DATABASE Statements 1 46 Syntax If you do not execute a CONNECT statement in your application the first SOL statement must be one of the following statements or a single statement PREPARE for one of the following statements DATABASE CREATE DATABASE START DATABASE DROP DATABASE If one of these database statements is the first SQL statement in an application the statement e
65. INFO statement 1 243S Accessing tables 12 16T ACOS function syntax in expression 1 458S use in expression 1 460S Action clause AFTER 1 117S definition of 1 116S FOR EACH ROW 1 116S subset syntax 1 121S syntax 1 116S Action statements in triggered action clause 1 1225 list of 1 122S order of execution 1 1225 Active set constructing with OPEN 1 2645 1 265S definition of 2 29T of a cursor 5 24T retrieving data with FETCH 1 194S 2 Index ADD CONSTRAINT keywords syntax in ALTER TABLE 1 15S AFTER action 1 117S keyword 1 117S Aggregate function ALL keyword syntax 1 462S and GROUP BY clause 3 5T AVG function syntax 1 462S description of 2 53T DISTINCT keyword syntax 1 462S in ESQL 1 467S 5 14T in EXISTS subquery 1 414S in expressions 1 314S in SELECT 1 315S in SPL expressions 14 21T in subquery 3 36T MAX function syntax 1 4625 MIN function syntax 1 462S null value signalled 5 12T restrictions in modifiable view 11 24T restrictions with GROUP BY 1 334S SUM function syntax 1 462S summary 1 465S Algebraic functions ABS function 1 445S MOD function 1 446S POW function 1 446S ROOT function 1 446S ROUND function 1 446S SORT function 1 447S syntax 1 4445 TRUNC function 1 447S Alias for a table in SELECT 1 323S for table name 2 79T to assign column names in temporary table 3 12T use in ORDER BY clause 1 338S use with GROUP BY clause 1 334S with self join 3 11T See also Synonym ALL keyword beginning a subqu
66. INSERT statement the cursor represents the rows that the INSERT statement is to add to the database When used with an EXECUTE PROCEDURE state ment the cursor represents the columns or values retrieved by the stored procedure The sum of the number of open cursors and the number of prepared statements that you can have at one time in one process is limited by the amount of free memory available in the system Use FREE statement id or FREE statement id variable to release the resources held by a prepared statement use FREE cursor id or FREE cursor variable to release resources held by a cursor A program can consist of one or more source code files By default the scope of a cursor is global to a program This means that a cursor declared in one file can be referenced from another file Ina multiple file program if you want to limit the scope of cursors to the files in which they are declared you must preprocess all the files with the local command line option See your ESOL product manual for more information restrictions and performance issues when preprocessing with the local option E C DECLARE A variable used in place of the cursor name or statement identifier must be of the CHARACTER data type In C it must be defined as exec sql char A variable used in place of the cursor name or statement identifier must be of the CHARACTER data type In COBOL such variables must be declared as a standard CHARACTER type You c
67. INTEGER REFERENCES orders order_num BEFORE user_id When you are referencing a primary key in another table you do not have to explicitly state the primary key columns in that table Referenced tables that do not specify the column referenced default to the primary key column In the previous example because order_num is the primary key in the orders table you do not have to reference that column explicitly When you place a referential constraint on a column or set of columns and a duplicate or unique index already exists on that column or set of columns the index is shared The data types of the referencing and referenced column must be identical unless the primary key column is of type SERIAL When you are adding a col umn that references a SERIAL column the column you are adding must be an INTEGER column Using the ON DELETE CASCADE Option 1 22 Syntax Cascading deletes allow you to specify whether you want rows deleted in the child table when rows are deleted in the parent table Normally you cannot delete data in the parent table if child tables are associated with the parent table You can decide whether you want the rows in the child table deleted ALTER TABLE with the ON DELETE CASCADE rule The ON DELETE CASCADE rule or cascading deletes means that when you delete a row in the parent table any rows associated with that row foreign keys in a child table are also deleted The principal advantage to the c
68. ON EXCEPTION statement to specify the actions that are taken for a particular error or a set of errors Syntax Statement ON EXCEPTION Block END EXCEPTION it p 1 72 J ae es IN error number C SOL WITH RESUME SET error A variable ne ISAM gt error A variable error data E variable error data is a literal string or a variable that contains a string variable returned by an SQL error error number is an SQL error number or an error number created by a RAISE EXCEPTION statement that is to be trapped ISAM error is an integer variable that receives the ISAM error number of variable the exception raised SQL error is an integer variable that receives the SQL error number of variable the exception raised Usage The ON EXCEPTION statement together with the RAISE EXCEPTION statement provides an error trapping and recovery mechanism for SPL The ON EXCEPTION statement defines a list of errors that are to be trapped as the procedure executes and specifies the action within the statement block to take when the trap is triggered If the IN clause is omitted all errors are trapped You can use more than one ON EXCEPTION statement within a given statement block SPL Statements 2 31 ON EXCEPTION The scope of an ON EXCEPTION statement is the statement block that follows the ON EXCEPTION statement all the statement blocks nested within that fol lowing statement block a
69. OPTIMIZATION statement to specify a high or low level of database server optimization Syntax SET OPTIMIZATION an fi LOW Usage You can execute a SET OPTIMIZATION statement at any time The optimization level carries across databases but applies only within the current database server After a SET OPTIMIZATION statement executes the new optimization level remains in effect until you enter another SET OPTIMIZATION statement or until the program ends The default database server optimization level HIGH remains in effect until you issue another SET OPTIMIZATION statement The LOW option invokes a less sophisticated but faster optimization algorithm The algorithm invoked by a SET OPTIMIZATION HIGH statement is a sophisticated cost based strategy that examines all reasonable choices and selects the best overall alternative For large joins this algorithm can incur more overhead than desired In extreme cases you can run out of memory The alternative algorithm invoked by a SET OPTIMIZATION LOW statement eliminates unlikely join strategies during the early stages which reduces the amount of time and resources spent during optimization However by spec ifying a low level of optimization you take the risk that the optimal strategy is not selected because it was eliminated from consideration during early stages of the algorithm The following example shows optimization across a network The central database on machine 1 is
70. References privilege you can limit the privileges by listing the names of specific columns Syntax 1 235 GRANT 1 236 Syntax If you are granting the Index privilege with the intent of allowing user to make changes to the underlying structure of a table be aware that user must also have the Resource privilege for the database to modify the database structure The table level privileges are defined in the following list INSERT DELETE SELECT UPDATE REFERENCES INDEX ALTER ALL provides the ability to insert rows provides the ability to delete rows provides the ability to name any column in SELECT statements You can restrict the Select privilege to one or more columns by listing them provides the ability to name any column in UPDATE statements You can restrict the Update privilege to one or more columns by listing them provides the ability to reference columns in referential constraints You must have the Resource privilege to take advantage of the References privilege However you can add a referential constraint during an ALTER TABLE state ment This does not require that you have the Resource priv ilege on the database You can restrict the References privilege to one or more columns by listing them You need only the References privilege to indicate cascading deletes You do not need the Delete privilege to place cascading deletes on a table provides the ability to create permanent indexe
71. Syntax Conventions 5 Example Code Conventions 10 Useful On Line Files 11 ASCII and PostScript Error Message Files 11 The Demonstration Database 12 Creating the Demonstration Database 13 Compliance with Industry Standards 14 New Features in Informix Version 6 0 Products That UseSQL 14 2 Introduction Structured Query Language SQL is an English like language that you can use when creating managing and using relational databases The SQL provided with Informix products is an enhanced version of the industry standard query language developed by International Business Machines Corporation IBM Informix Products That Use SOL Informix produces many application development tools and SQL application programming interfaces API Application development tools currently available include products like INFORMIX SQL INFORMIX 4GL and the Interactive Debugger SQL APIs currently available include INFORMIX ESQL C and INFORMIX ESQL COBOL Informix products work with a database server either INFORMIX OnLine Dynamic Server or INFORMIX SE The DB Access database access utility is shipped as a part of each database server If you are running client applications developed with Version 4 1 and 5 0 application development tools you use INFORMIX NET to connect the client to the network Products Included in This Manual All of the information presented in this manual is valid for the following products Differences in their use of SQL ar
72. TRACE statement with an expression after previously using a TRACE OFF statement CREATE PROCEDURE tracing DEFINE i INT BEGIN ON EXCEPTION IN 1 END EXCEPTION do nothing TRACE OFF SET DEBUG FILE TO tmp foo trace TRACE Forloop starts FOR i IN 1 TO 1000 BEGIN TRACE FOREACH starts FOREACH SELECT INTO a FROM t IF lt some condition gt THEN RAISE EXCEPTION 1 emergency exit END IF FOREACH END return some value END FOR do something END END PROCEDURE 2 44 SPL Statements TRACE The following example shows additional TRACE statements CREATE PROC DEFIN ry TRACE SET D TRACE O EB TRACE LET i TRACE LET i TRACE TRACE TRACE SET DEB END PROCEDU E o EDURE testproc i INT FF UG FILE TO tmp test trace E ntering foo ROCEDURE testtoo itl itl Exiting testproc UG FILE TO tmp test2 trace RE Looking at the Traced Output To see the traced output use an editor or utility to display or read the contents of the file SPL Statements 2 45 WHILE WHILE Purpose Syntax Usage 2 46 SPL Statements Use the WHILE statement to establish an indefinite loop within a procedure Condition Statement WHILE i Block END WHILE p 1 404 p 1 72 a J The condition is evaluated once at the be
73. This data file conveys the following information e Indicates a serial field by specifying a zero 0 Uses the vertical bar the default delimiter character e Assigns null values to the phone field for the first row and the address2 field for the second row The null values are shown by two delimiter characters with nothing between them Syntax 1 257 LOAD The following statement loads the values from the new_custs file into the customer table owned by jason LOAD FROM new_custs INSERT INTO jason customer DELIMITER Clause Use the DELIMITER clause to specify the delimiter that separates the data contained in each column in a row in the input file If you omit this clause your Informix product checks the DBDELIMITER environment variable If the DBDELIMITER environment variable has not been set the default delimiter is the vertical bar ASCII 124 See Chapter 4 in the Informix Guide to SQL Reference for information about how to set the DBDELIMITER environment variable You can specify TAB CTRL D or lt blank gt ASCII 32 as the delimiter symbol You cannot use the following items as the delimiter symbol backslash newline CTRL J hex numbers 0 9 a f A F The following statement identifies the semicolon as the delimiting character LOAD FROM a data ord loadfile DELIMITER INSERT INTO orders INSERT INTO Clause 1 258 Syntax Use the INSERT INTO clause to
74. You can use letters characters and underscores _ for the rest of the name DB Access makes no distinction between uppercase and lowercase letters e The database name should be unique When you run dbaccessdemo6 you are as the creator of the database the owner and Database Administrator DBA of that database If you installed your Informix database server product according to the installation instructions the files that make up the demonstration database are protected so you cannot make any changes to the original database You can run the dbaccessdemo6 script again whenever you want to work with a fresh demonstration database The script prompts you when the cre ation of the database is complete and asks if you would like to copy the The Demonstration Database sample command files to the current directory Enter N if you have made changes to the sample files and do not want them replaced with the original versions Enter Y if you want to copy over the sample command files Creating the Demonstration Database Use the following steps to create and populate the demonstration database 1 Set the INFORMIXDIR environment variable so that it contains the name of the directory in which your Informix products are installed Set INFOR MIXSERVER to the name of the default database server The name of the default database server must exist in the INFORMIXDIR etc sqlhosts file For a full description of environmen
75. accordingly CREATE PROCEDURE two_returns stockno INT RETURNING CHAR 15 DEFINE des CHAR 15 O EXCEPTION 272 if user doesn t have select privs RETURN return no values END EXCEPTION SELECT DISTINCT descript INTO des FROM stock WHERE stocknum stockno RRETURN des END PROCEDURE RETURN A RETURN statement without any expressions exits only if the procedure is declared not to return values otherwise it returns nulls The WITH RESUME Keyword If you use the WITH RESUME keyword after the RETURN statement executes the next invocation of this procedure upon the next FETCH or FOREACH statement starts from the statement following the RETURN statement If a procedure executes a RETURN WITH RESUME statement it must be called from a FOREACH loop in the calling procedure or program If a procedure executes a RETURN WITH RESUME statement it can be called with a FETCH statement in an application written in an SQL API The following example shows a cursory procedure that can be called by another procedure After the RETURN i WITH RESUME statement returns each value to the calling procedure the next time sequence is called the next line of sequence is executed If backwards equals 0 no value is returned to the calling procedure and execution of sequence stops CREATE PROCEDURE sequence limit INT backwards INT RETURNING INT DEFINE i INT
76. an Update Cursor The FOR UPDATE keywords notify the database server that updating is possible causing it to use more stringent locking than with a select cursor You are not allowed to modify data through a cursor without this clause You can specify particular columns that can be updated After you create an update cursor you can update or delete the currently selected row by using an UPDATE or DELETE statement with the WHERE CUR RENT OF clause The words CURRENT OF refer to the row that was most recently fetched they take the place of the usual test expressions in the WHERE clause An update cursor allows you to perform updates that are not possible with the UPDATE statement because both the decision to update and the values of the new data items can be based on the original contents of the row The UPDATE statement cannot interrogate the table being updated All simple select cursors are potentially update cursors even if they are declared without the FOR UPDATE keywords See the restrictions on SELECT statements in the following section Subset of the SELECT Statement Associated with an Update Cursor Not all SELECT statements can be associated with an update cursor The SELECT statement included in the DECLARE statement either directly or as a prepared statement must conform to the following restrictions e You can select data from only one table e The statement cannot include any aggregate functions AVG COUNT MAX MIN
77. are released only when the transaction commits or rolls back Repeatable Read is the default isolation level in an ANSI compliant database Syntax 1 367 SET ISOLATION Default Isolation Levels The default isolation level for a particular database is established when you create the database according to database type The default isolation level for each database type is described in the following list DIRTY READ is the default level of isolation in a database without logging COMMITTED READ is the default level of isolation in a database with logging that is not ANSI compliant REPEATABLE READ is the default level of isolation in an ANSI compliant database The default level remains in effect until you issue a SET ISOLATION statement After a SET ISOLATION statement executes the new isolation level remains in effect until you enter another SET ISOLATION statement or until the end of the program Effects of Isolation Levels 1 368 Syntax You cannot set the database isolation level in a database that does not have logging Every retrieval in such a database occurs as a Dirty Read You can issue a SET ISOLATION statement from a client machine only after a database has been opened The data obtained during binary large object blob retrieval can vary depending on the database isolation level Under Dirty Read or Committed Read levels of isolation a process is permitted to read a blob that is either deleted if the de
78. are returned by default ALL specifies that all selected values are returned regardless of whether duplicates exist ALL is the default state DISTINCT eliminates duplicate rows from the query results UNIQUE eliminates duplicate rows from the query results UNIQUE is a synonym for DISTINCT For example the following query lists the stock_num and manu_code of all items that have been ordered excluding duplicate items SELECT DISTINCT stock_num manu_code FROM items You can use the DISTINCT or UNIQUE keywords once in each level of a query or subquery For example the following query uses DISTINCT in both the query and the subquery SELECT DISTINCT stock_num manu_code FROM items WHERE order_num SELECT DISTINCT order_num FROM orders WHERE customer_num 120 Expressions in the Select List You can use any of the five basic types of expressions column constant function aggregate function and stored procedure or combinations thereof in the select list The five expression types are described in detail beginning with the section Expression on page 1 430 The following sections present examples of using each type of simple expression in the select list You can combine simple numeric expressions by connecting them with arithmetic operators for addition subtraction multiplication and division However if you combine a column expression and an aggregate function you must include the column expre
79. as with The following two examples show how to use the keyword CREATE or GRANT as a table alias Using create as a table alias causes the following example to fail because the database server interprets the keyword as part of the syntax to create an entity such as a table synonym or view exec sql select from mytab create fails The workaround in the following example uses the keyword AS to identify create as a table alias exec sql select from mytab as create Identifier Fetching Keywords as Cursor Names In a few situations no workaround exists for the syntactic ambiguity that occurs when a keyword is used as an identifier in an SQL program In the following example the FETCH statement generates a syntax error because the preprocessor interprets the syntax as pertaining to a scroll cursor and expects a cursor name to follow next This occurs whenever the keyword NEXT PREVIOUS PRIOR FIRST LAST CURRENT RELATIVE or ABSOLUTE is used as a cursor name exec sql declare next cursor for select customer_num lname from customer exec sql open next exec sql fetch next into cnum lname Using Keywords as Procedure Variable Names If you use any of the following keywords as identifiers for variables in a procedure you can create ambiguous syntax CURRENT OFF DATETIME ON GLOBAL PROCEDURE INTERVAL SELECT NULL Syntax 1 479 Identifier Using CURRENT DATETIME INTERVAL and NULL
80. clause it returns DBSERVERNAME for every row in the table If you add the DISTINCT keyword to the SELECT clause the query returns DBSERVERNAME once The second statement adds a row that con tains the current site name to a table The third statement returns all the rows that have the site name of the current system in site_col The last statement changes the company name in the customer table to the current system name ECT DBSERVERNAME FROM customer ERT INTO host_tab VALUES 1 DBSERVERNAME ECT FROM host_tab WHER DBS ERV ERNAM E site_col L PDATE cu DBSERVERNAME stomer SET company WHERE customer_num 120 Literal Number as an Expression The following examples show literal numbers as expressions NS ECT unit_price 5 ERT INTO items VALUI ERT INTO acreage VAI ES 4 35 52 HRO 12 4 00 LUES 4 5 2e4 FROM stock ECT 1 balance FROM accounts TODAY Function Use the TODAY function to specify TODAY as a default return the system date as a DATE type If you value for a column it must be a DATE column Syntax 1 439 Expression The following examples show how you might use the TODAY function in an INSERT UPDATE or SELECT statement UPDATE orders order_date SET order_date TODAY WHERE order_num 1005 INSERT INTO orders VALUES 0 TODAY 120 NULL N 1AUE217 NULL NULL NULL NULL SELEC
81. close sel_curs exec sql free sel_curs Freeing a Cursor 1 208 Syntax If you declared a cursor for a prepared statement freeing the cursor releases only the resources in the database server To release the resources for the statement in the application development tool use FREE statement id or statement id variable FREE If acursor is not declared for a prepared statement freeing the cursor releases the resources in both the application development tool and the database server After a cursor is freed it cannot be opened until it is declared again It is recommended that the cursor be explicitly closed before it is freed References See the CLOSE DECLARE EXECUTE EXECUTE IMMEDIATE and PREPARE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of the FREE statement in Chapter 5 Syntax 1 209 GET DESCRIPTOR GET DESCRIPTOR Purpose Use the GET DESCRIPTOR statement to accomplish the following separate tasks Determine how many values are described in a system descriptor area by retrieving the value in the COUNT field Determine the characteristics of each column or expression described in the system descriptor area Copy a value out of the system descriptor area and into a host variable after a FETCH statement 1 210 Syntax Syntax EZ GET DESCRIPTOR descriptor host variable COUNT T variable VALUE item scribed number Item Inf
82. column CREATE TABLE Using the ON DELETE CASCADE Option Cascading deletes allow you to specify whether you want rows deleted in the child table when rows are deleted in the parent table Unless you specify cas cading deletes the default prevents you from deleting data in the parent table if child tables are associated with the parent table With the ON DELETE CAS CADE clause when you delete a row in the parent table any rows associated with that row foreign keys in a child table are also deleted The principal advantage to the cascading deletes feature is that it allows you to reduce the quantity of SQL statements you need to perform delete actions The ON DELETE CASCADE option is not available in INFORMIX SE databases For example the all_candy table contains the candy_num column as a primary key The hard_candy table refers to the candy_num column as a for eign key The CREATE TABLE statement shown in the following example cre ates the hard_candy table with the cascading delete option on the foreign key CREATE TABLE hard_candy candy_num INT candy_flavor CHAR 20 FOREIGN KEY candy_num REFERENCES all_candy ON DELETE CASCADE With cascading deletes specified on the child table in addition to deleting a candy item from the all_candy table the delete cascades to the hard_candy table associated with the candy_num foreign key You specify cascading deletes with the REFERENCES clause on a column level
83. cursor for sel_l Using Cursors with Transactions To roll back a modification you must perform the modification within a transaction A transaction begins only when the BEGIN WORK statement is executed In ANSI compliant databases transactions are always in effect Syntax 1 155 DECLARE 1 156 Syntax The database server enforces the following guidelines for select and update cursors These guidelines ensure that modifications can be committed or rolled back properly Open an insert or update cursor within a transaction Include PUT and FLUSH statements within one transaction Modify data update insert or delete within one transaction The database server permits you to open and close a hold cursor for an update outside a transaction however you should fetch all the rows that per tain to a given modification and then perform the modification all within a single transaction You cannot open and close cursors that are not hold or update cursors outside a transaction The following example produces an error when the database server tries to execute the update line exec sql declare q_curs cursor for select customer_num fname lname from customer where lname matches last_name for update exec sql open q_curs exec sql fetch q_curs into cust_rec fetch before begin exec sql begin work exec sql update customer set lname Smith where current of q_curs error here exec sql commit work
84. customer_num and displays the output of the procedure under the label n_orders SELECT customer_num lname get_orders customer_num n_orders FROM customer Syntax 1 315 SELECT Selecting Expressions That Use Arithmetic Operators You can combine numeric expressions with arithmetic operators to make complex expressions You cannot combine expressions that contain aggre gate functions with column expressions The following examples show expressions that use arithmetic operators within a select list SELECT stock_num quantity total_price FROM customer SELECT price 2 doubleprice FROM items SELECT count 2 FROM customer SELECT count LENGTH ab FROM customer Using a Display Label 1 316 Syntax If you are creating a temporary table you must supply a display label for any columns that are not simple column expressions The display label is used as the name of the column in the temporary table A display label appears as the heading for that column in the output of the SELECT statement The value of display label is stored in the sqiname field of the sqlda structure See your SQL API product manual for more information on the sqlda struc ture If you are using the SELECT statement in creating a view do not use display labels Specify the desired label names in the CREATE VIEW column list instead Using the AS Keyword If your display label is also a keyword you can use the AS keyword wi
85. database In SQL APIs the CREATE DATABASE statement cannot appear in a multistatement PREPARE operation CREATE DATABASE ANSI Compliant Databases You have the option of creating an ANSI compliant database ANSI compliant databases are set apart from non ANSI databases by the following features e Allstatements are contained in transactions automatically All databases on the INFORMIX OnLine Dynamic Server use unbuffered logging Owner naming is enforced You must use the owner name when referring to each table view synonym index or constraint unless you are the owner e For databases on an OnLine database server the default isolation level available is repeatable read Default privileges on objects differ from those in databases that are not ANSI compliant Users do not receive PUBLIC privilege to tables and synonyms by default Other slight differences exist between databases that are and are not ANSI compliant These differences are noted as appropriate with the related SQL statement Logging on INFORMIX OnLine Dynamic Server In the event of a failure INFORMIX OnLine Dynamic Server uses the log to re create all committed transactions in your database If you do not specify the WITH LOG statement you cannot use transactions or the statements associated with databases that have logging BEGIN WORK COMMIT WORK ROLLBACK WORK SET LOG and SET ISOLATION Designating Buffered Logging The following exa
86. drop an existing constraint specify the DROP CONSTRAINT keywords and the name of the constraint The following statement is an example of dropping a constraint ALTER TABLE manufact DROP CONSTRAINT con_name If a constraint name is not specified when the constraint is created the database server generates the name You can query the sysconstraints system catalog table for the names including the owner of constraints For example to find the name of the constraints placed on the items table you can issue the following statement SELECT constrname FROM sysconstraints WHERE tabid SELECT tabid FROM systables WHERE tabname items When you drop a unique or primary key constraint that has a corresponding foreign key those referential constraints are dropped For example if you drop the primary key constraint on the order_num column in the orders table and order_num exists in the items table as a foreign key that referential relationship is also dropped 1 32 Syntax ALTER TABLE MODIFY NEXT SIZE Clause MODIFY NEXT SIZE Clause p MODIFY NEXT SIZE kbytes kbytes is the size in kilobytes that you want to assign for the next extent for this table Use the MODIFY NEXT SIZE clause to change the size of new extents When you want to specify an extent size of 32 kilobytes use a statement such as the following example ALTER TABLE customer MODIFY NEXT SIZE 32 T
87. ends You can declare both sequential and scroll cursors with the WITH HOLD keywords The following example creates a hold cursor DECLARE hld_cur CURSOR WITH HOLD FOR SELECT customer_num lname city FROM customer A hold cursor allows uninterrupted access to a set of rows across multiple transactions Ordinarily all cursors close at the end of a transaction a hold cursor does not close You can use a hold cursor as shown in the following fragment of ESQL C code The code fragment uses a hold cursor as a master cursor to scan one set of records and a sequential cursor as a detail cursor to point to records that are located in a different table The records that are scanned by the master cursor are the basis for updating the records pointed to by the detail cursor In the following example the COMMIT WORK state ment at the end of each iteration of the first WHILE loop leaves the hold cursor c_master open but closes the sequential cursor c_detail and releases all locks DECLARE This technique minimizes the resources that the database server must devote to locks and unfinished transactions and it gives other users immediate access to updated rows exec sq begin declare section int p_custnum int save_status long p_orddate exec sql end declare section exec sql prepare st_l from select order_date from orders where customer_num for update exec sql declare c_detail cursor for st_l exec sql declare c_maste
88. found SO 011 Index already exists so 021 Column already exists S1 001 Memory allocation failure IX 000 Informix reserved error or warning message Using SQLSTATE in Applications You can use a variable called SQLSTATE that you do not have to declare in your program SQLSTATE contains the error code essential for error han dling that is generated every time your program executes an SQL statement 1 220 Syntax GET DIAGNOSTICS SQLSTATE is created automatically where RETURNED_SOLSTATE contains the SQLSTATE error status code as if the following GET DIAGNOSTICS statement has been executed EXEC SQL get diagnostics exception 1 SQLSTATE RETURNED_SQLSTATE You can examine the SQLSTATE variable to determine whether an SQL statement was successful If the SQLSTATE variable indicates that the state ment failed you can execute a GET DIAGNOSTICS statement to obtain additional error information An alternative to using the SQLSTATE variable that is created for you is to declare a host variable within your application to receive the RETURNED_SQLSTATE value The value in the RETURNED_SQLSTATE field of the GET DIAGNOSTICS statement provides the error code that is essential for error handling You can assign this host variable any valid name including the name SQLSTATE If you declare a host variable however you must explic itly issue the GET DIAGNOSTICS statement after each SQL statement that you wish to che
89. gathered about the column The data in the systables syscolumns and sysindexes tables is updated No information is put into the sysdistrib system catalog table If data already exists in the sysdistrib system catalog table when you run an UPDATE STATISTICS LOW statement the distribution data remains intact unless the DROP DISTRIBU TIONS option is used If the DROP DISTRIBUTIONS option is specified but no table name is specified all the distribution information is removed The UPDATE STATISTICS LOW statement updates table row and page counts as well as index and column statistics for specified columns If you want the UPDATE STATISTICS statement to do minimal work specify a column that is not part of an index The following example updates statistics on the customer_num column of the customer table All distributions associated with the customer table remain intact even those that already exist on the customer_num column UPDATE STATISTICS LOW FOR TABLE customer customer_num Syntax 1 395 UPDATE STATISTICS Dropping Data with the DROP DISTRIBUTIONS Clause If you want to drop distribution data for some or all the columns already defined in the sysdistrib table and yet you want to update the statistics with the LOW option for the rest of the columns in the table you can use the DROP DISTRIBUTIONS clause If you specify the DROP DISTRIBUTIONS keyword all distribution information existing for the column specified in
90. has a unique constraint on one of its columns CREATE TABLE accounts a_name CHAR 12 a_code SERIAL UNIQUE a_name CONSTRAINT acc_name 1 92 Syntax CREATE TABLE If you want to define the constraint at the column level instead you simply include the keywords UNIQUE and CONSTRAINT in the column definition as shown in the following example CREATE TABLE accounts a_name CHAR 12 UNIQUE CONSTRAINT all_name a_code SERIAL You cannot place a unique constraint on a BYTE or TEXT column Defining a Column as a Primary Key A primary key is a column or set of columns that contains a non null unique value for each row ina table A table can have only one primary key and a col umn that is defined as a primary key cannot also be defined as unique In the previous two examples a unique constraint was placed on the column a_name The next example creates this column as the primary key for the accounts table CREATE TABLE accounts a_name CHAR 12 a_code SERIAL PRIMARY KEY a_name You cannot place a primary key constraint on a BYTE or TEXT column Defining a Column as a Foreign Key A foreign key joins and establishes dependencies between tables A foreign key references a unique or primary key in a table For every entry in the for eign key columns a matching entry must exist in the unique or primary key columns if all foreign key columns contain non null values You cannot make BYTE or T
91. if the UPDATE statement fails after updating some rows the successfully updated rows remain in the table You cannot automatically recover from a failed update UPDATE Updating Rows in a Database with Transactions If you are updating rows in a database with transactions and you are using transactions you can undo the update using the ROLLBACK WORK state ment If you do not execute a BEGIN WORK statement before the update and the update fails the database server automatically rolls back any database modifications made since the beginning of the update If you are updating rows in an ANSI compliant database transactions are implicit and all database modifications take place within a transaction In this case if an UPDATE statement fails you can use the ROLLBACK WORK statement to undo the update If you are using INFORMIX OnLine Dynamic Server and you are within an explicit transaction and the update fails the database server automatically undoes the effects of the update Locking Considerations If you are using an INFORMIX OnLine Dynamic Server database server when a row is selected with the intent to update the update process acquires an update lock Update locks permit other processes to read or share a row that is about to be updated but do not let those processes update or delete it Just before the update occurs the update process promotes the shared lock to an exclusive lock An exclusive lock prevents other processes
92. in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S Update privilege column level 11 10T definition of 1 236S 11 8T with a view 1 384S 11 28T UPDATE REFERENCING clause and FOR EACH ROW section 1 121S correlation name 1 120S syntax 1 120S UPDATE statement and end of data 6 14T and transactions 1 384S applied to view 11 24T as triggered action 1 1225 as triggering statement 1 1125 1 114S 1 115S Cee Cee eS Index 47 description of 4 12T embedded 6 14T to 6 17T in trigger event 1 111S locking considerations 1 385S missing WHERE signalled 5 10T multiple assignment 4 14T number of rows 5 12T preparing 5 30T privilege for 11 6T 11 8T restrictions on columns for update 1 153S restrictions on subqueries 4 13T rolling back updates 1 385S syntax 1 383S time to update indexes 10 20T updating a column to null 1 387S updating through a view 1 384S updating with cursor 1 390S use of expressions 1 388S with Condition segment 1 404S FETCH 1 201S SET keyword 1 3865 WHERE CURRENT OF keywords 1 390S WHERE keyword 1 388S with a select for update 1 340S with an update cursor 1 152S UPDATE STATISTICS statement affect on sysdistrib 2 19R and DBUPSPACE environment variable 4 30R creating distributions 1 396S dropping data distributions 1 396S examining index pages 1 394S optimizing search strategies 1 3945 syntax 1 392S using the LOW keyword 1 395S when to execute 1 395S Update trigger defining
93. in INSERT You cannot use the CURRENT DATETIME INTERVAL or NULL keyword as the name of a procedure with the INSERT statement For example if you define a variable called null when you try to insert the value null into a column you receive a syntax error This is shown in the following example CREATE PROCEDURE problem DEFINE null INT LET null 3 INSERT INTO tab VALUES null error inserts NULL not 3 Using NULL and SELECT in a Condition 1 480 Syntax If you define a variable with the name null or select using it in a condition that uses the IN keyword is ambiguous The following example shows three con ditions that cause problems in an IF statement in a WHERE clause of a SELECT statement and in a WHILE condition CREATE PROCEDURE problem DEFINE x y select null INT DEFINE pfname CHAR 15 LET x 3 LET select 300 LET null 1 IF x IN select 10 12 THEN LET y 1 problem if IF x IN 1 2 4 THEN SELECT customer_num fname INTO y pfname FROM customer WHERE customer IN select 301 302 303 problem in WHILE x IN null 2 problem while END WHILE Identifier You can use the variable select in an IN list if you ensure it is not the first element in the list The workaround in the following example corrects the IF statement shown in the preceding example IF x IN 10 select 12 THEN LET y 1 problem if No workar
94. in SQLAWARN 5 12T restrictions in INSERT 4 10T restrictions in prepared statement 5 29T retrieving multiple rows 5 20T retrieving single rows 5 13T syntax in FETCH 1 194S in SELECT 1 310S use in FETCH 1 199S in SELECT 1 318S INTO TEMP keywords description of 2 83T restrictions in view 11 22T syntax in SELECT 1 310S use in SELECT 1 3415 with UNION operator 1 3445 IS keyword in Condition segment 1 409S with WHERE keyword 1 327S IS NULL keywords 1 327S ISAM error code 2 315 2 36S 5 12T Isolation level Committed Read 1 367S 7 10T Cursor Stability 1 367S 7 11T default in ANSI compliant database 1 13R definitions 1 367S description of 7 9T Dirty Read 1 3675 7 10T in external tables 1 368S Repeatable Read 1 3675 7 12T setting 7 9T use with FETCH statement 1 201S items table in stores6 database columns in A 3R ITYPE field SET DESCRIPTOR statement 1 357S setting with SET DESCRIPTOR 1 359S with X Open programs 1 213S J Join associative 2 76T creating 2 71T definition of 2 8T dominant table 3 21T effect of large join on optimization 13 36T equi join 2 71T in Condition segment 1 331S multiple table join 1 332S 2 77T natural 2 75T nested outer 3 28T nested simple 3 25T outer 3 21T outer join 1 333S restrictions in modifiable view 11 24T self join 1 333S 3 11T sort merge 13 27T subservient table 3 21T two table join 1 332S Join column See Foreign key Join condition See Condition segment Journal
95. is called a subquery You can use a subquery in a SELECT statement to perform the following functions Compare an expression to the result of another SELECT statement Determine whether an expression is included in the results of another SELECT statement e Ask whether any rows are selected by another SELECT statement The subquery can depend on the current row being evaluated by the outer SELECT statement in this case the subquery is a correlated subquery The kinds of subquery conditions are shown in the following example with their syntax A subquery can return a single value no value or a set of values depending on the context in which it is used If a subquery returns a value it must select only a single column If the subquery simply checks whether a row or rows exists it can select any number of rows and columns A subquery cannot con tain an ORDER BY clause The full syntax of the SELECT statement is described on page 1 310 Syntax 1 413 Condition IN Subquery IN Subquery Expression IN Qondition gt p 1 wi gt i ae y Subquery NOT p 1 413 An IN subquery condition is true if the value of the expression matches one or more of the values selected by the subquery The subquery must return only one column but it can return more than one row The keyword IN is equivalent to the ANY sequence The keywords NOTIN are equivalent to the ALL sequence See the
96. loop_skip RETURNING INT DEFINE i INT FOR i IN 3 TO 15 STEP 2 INSERT INTO testtable values i null null IF i 11 CONTINUE FOR END IF RETURN i WITH RESUME END FOR END PROCEDURE The CONTINUE statement generates errors if it cannot find the identified loop 2 6 SPL Statements DEFINE DEFINE Purpose Use the DEFINE statement to declare variables that are used in the procedure and assign them data types Syntax P SQL Data Type Default variable _ Defau DEFINE GLOBAL aran ee DEFAULT Value 7 3 4 DEFAULT J REFERENCES BYTE NULL q aeg J 3 SQL Data Type variable Subset J name 5 p N oy REFERENCES T BYTE ay Ne Table Name LIKE p 1 506 column Synonym Name p 1 504 View Name p 1 510 N PROCEDURE J column is the name of a column in the table variable name is the name of the procedure variable being defined SPL Statements 2 7 DEFINE Default Value Literal Number a N p 1 493 7 Ks QuotedString J p 1 497 K Literal Interval A p 1 490 Ne Literal Datetime A p 1 487 K CURRENT A p 1 440 g DATETIME Field Qualifier N USER A N TODAY N NULL A Ko DBSERVERNAME XN SITENAME fl Usage The DEFINE statement is not an executable statement The DEFINE statem
97. month day and year The first expression must evaluate to an integer representing the number of the month 1 to 12 The second expression must evaluate to an integer representing the number of the day of the month 1 to 28 29 30 or 31 as appropriate for the month The third expression must evaluate to a four digit integer representing the year You cannot use a two digit abbreviation for the third expression The following example sets the paid_date associated with the order number 8052 equal to the first day of the present month UPDATE orders SET paid_date MDY MONTH TODAY 1 YEAR TODAY WHERE po_num 8052 Trigonometric Functions 1 458 Syntax A trigonometric function expression takes an argument as shown in the following example Trigonometric unctions gt cos radian pe N expression SIN TAN KN ASIN numeric A expression ACOS ATAN S amn yx _ __7 numeric is an expression that evaluates to a value between 1 and 1 expression inclusive radian is the number of radians expression Expression If you are using degrees and want to convert degrees to radians use the following example degrees 180 radians If you are using radians and want to convert radians to degrees use the following formula radians 180 nm degrees x is a numeric expression representing the x coordinate of the rectangular coordi
98. must be unique that is a view name cannot be the same name as another database object such as a table synonym or temporary table 1 136 Syntax CREATE VIEW Data types of the columns of the view are inherited from the tables from which they come Data types of virtual columns are determined from the nature of the expression You must have the Select privilege on all columns from which the view is derived to create a view The SELECT statement is stored in the sysviews system catalog table When you subsequently refer to a view in another statement the database server performs the defining SELECT statement while it executes the new statement You cannot use a ROLLBACK WORK statement to undo a CREATE VIEW statement If you roll back a transaction that contains a CREATE VIEW statement the view remains and you do not receive an error message BZ if you create a view outside the CREATE SCHEMA statement you receive warnings if you use the ansi flag or set DBANSIWARN Subset of a SELECT Allowed in CREATE VIEW The SELECT statement is a statement of the form described on page 1 310 except that it cannot have an ORDER BY clause INTO TEMP clause or UNION operator Do not use display labels in the select list display labels are interpreted as column names Naming View Columns If you do not specify a list of columns for view name the view inherits the column names of the underlying tables In the following example the view h
99. one row hence 100 for end of data is never returned into the sqlcode variable for a first fetch attempt You can also use the GET DIAGNOSTICS statement for error checking See the GET DIAGNOSTICS statement in this manual Using Arithmetic Operators with Expressions You can combine expressions with arithmetic operators to make complex expressions You cannot combine expressions that use aggregate functions with column expressions The following examples use arithmetic operators quantity total_price price 2 COUNT 2 If any value that participates in an arithmetic expression is null the value of the entire expression is null as shown in the following example SELECT order_num ship_charge ship_weight FROM orders WHERE order_num 1023 If either ship_charge or ship_weight is null the value returned for the expression ship_charge ship_weight is also null If the expression ship_charge ship_weight is used in a condition its truth value is unknown If you combine a DATETIME value with one or more INTERVAL values all the fields of the INTERVAL value must be present in the DATETIME value no implicit EXTEND function is performed In addition you cannot use YEAR to MONTH intervals with DAY to SECOND intervals Syntax 1 467 Expression Procedure Call Expressions 1 468 Syntax The following diagram shows procedure call expressions gt _ ame p 1 495 J P d r cedure a
100. or SUM e The statement cannot include any of the following clauses or keywords DISTINCT INTO TEMP UNION GROUP BY ORDER BY UNIQUE For a complete description of SELECT syntax and usage see the SELECT statement on page 1 310 Locking with an Update Cursor You declare an update cursor to let the database server know that the program might update or delete any row that it fetches as part of the SELECT statement The update cursor employs promotable locks for rows that 1 152 Syntax DECLARE are fetched Other programs can read the locked row but no other program can place a promotable or write lock Before the row is modified the row lock is promoted to an exclusive lock The INFORMIX SE database server does not use promotable locks Before the program modifies a row the database server obtains an exclusive lock on the row Although it is possible to declare an update cursor WITH HOLD the only reason for doing so is to break a long series of updates into smaller transac tions You must fetch and update a particular row in the same transaction If an operation involves fetching and updating a very large number of rows the lock table maintained by the database server can overflow The usual way to prevent this overflow is to lock the entire table being updated If this is impossible an alternative is to update through a hold cursor and to execute COMMIT WORK at frequent intervals However you must plan such an appli ca
101. or table level constraint You need only the References privilege to indicate cascading deletes You do not need the Delete privilege to perform cascading deletes however you do need the Delete privilege on tables referenced in the DELETE statement After you indicate cascading deletes when you delete a row from a parent table INFORMIX OnLine Dynamic Server deletes any associated matching rows from the child table Syntax 1 97 CREATE TABLE What Happens to Multiple Child Tables If you have a parent table with two child constraints one child with cascading deletes specified and one child without cascading deletes and you attempt to delete a row from the parent table that applies to both child tables then the delete statement fails and no rows are deleted from either the parent or child tables Locking and Logging During deletes the database server places locks on all qualifying rows of the referenced and referencing tables You must turn logging on when you per form the deletes If logging is turned off in a database even temporarily deletes do not cascade This restriction applies because if logging is turned off you have no way to roll back actions For example if a parent row is deleted and the system crashes before the children rows are deleted the data base has dangling children records which violates referential integrity However when logging is turned back on subsequent deletes can cascade Restriction on Cascad
102. other processes read access to the table but denies write access Other processes cannot update or delete data if a table is locked in Shared mode The EXCLUSIVE keyword locks a table in Exclusive mode Exclusive mode denies other processes both read and write access to the table Exclusive mode locking automatically occurs when you execute the ALTER INDEX CREATE INDEX DROP INDEX RENAME COLUMN RENAME TABLE and ALTER TABLE statements The INFORMIX SE database server does not permit more than one user to lock a table in Shared mode 1 260 Syntax LOCK TABLE Databases with Transactions If your database was created with transactions the LOCK TABLE statement succeeds only if it executes within a transaction You must issue a BEGIN WORK statement before you can execute a LOCK TABLE statement Transactions are implicit in an ANSI compliant database The LOCK TABLE statement succeeds whenever the specified table is not already locked by another process The following guidelines apply to the use of the LOCK TABLE statement within transactions e You cannot lock system catalogs e You cannot switch between shared and exclusive table locking within a transaction For example once you lock the table in Shared mode you cannot upgrade the lock mode to Exclusive e If you issue a LOCK TABLE statement before you access a row in the table no row locks are set for the table In this way you can override row level locking and preve
103. statement a procedure cursor that returns values or an INSERT statement an insert cursor You can use a select cursor to update or delete rows then it is called an update cursor A cursor can also be associated with a statement identifier enabling you to use a cursor with INSERT SELECT or EXECUTE PROCEDURE statements that are prepared dynamically and to use different statements with the same cur sor at different times In this case the type of cursor depends on the statement that is prepared at the time the cursor is opened see the OPEN statement on page 1 263 Note Cursors for stored procedures behave the same as select cursors excluding update cursors Select or Procedure Cursor A select or procedure cursor enables you to scan multiple rows of data moving data row by row into a set of receiving variables as described in the following steps 1 Use a DECLARE statement to define a cursor for the SELECT statement 2 Open the cursor with the OPEN statement The database server processes the query to the point of locating or constructing the first row of the active set 3 Retrieve successive rows of data with the FETCH statement 4 Close the cursor with the CLOSE statement when the active set is no longer needed Update Cursor 1 148 Syntax An update cursor is declared using the FOR UPDATE keywords Using the update cursor you can modify update or delete the current row Inan ANSI compliant database you ca
104. statement only at the end of a multistatement operation The ROLLBACK WORK statement releases all row and table locks held by the cancelled transaction If you issue a ROLLBACK WORK statement when no transaction is pending an error occurs In an ANSI compliant database transactions are implicit Transactions start after each COMMIT WORK or ROLLBACK WORK statement If you issue a ROLLBACK WORK statement when no transaction is pending the statement is accepted but has no effect ROLLBACK WORK If you are using INFORMIX SE a ROLLBACK WORK statement undoes all database changes except those that result from GRANT or REVOKE state ments or from data definition statements Data definition statements are treated as single transactions If they execute successfully they are commit ted automatically and cannot be rolled back by the ROLLBACK WORK state ment Data definition statements include statements that modify the number names or indexes of tables and statements that modify the num ber names or data types of columns For a list of data definition statements see Data Definition Statements on page 1 5 If a transaction rolls back the actions taken to undo the transaction are also logged to table audit trails if any exist The ROLLBACK WORK statement closes all open cursors except those declared with hold which remain open despite transaction activity If you use the ROLLBACK WORK statement within a routine called by a WHE
105. system descriptor area see your SQL API manual Syntax 1 203 FLUSH FLUSH Purpose Syntax Usage Use the FLUSH statement to force rows that were buffered by a PUT statement to be written to the database ESQL FLUSH cursor i cursor variable cursor id is the identifier of a cursor that is associated with an INSERT statement cursor variable is an embedded variable name that identifies a cursor that is associated with an INSERT statement The PUT statement adds a row to a buffer and the buffer is written to the database when it is full Use the FLUSH statement to force the insertion when the buffer is not full If the program terminates without closing the cursor the buffer is left unflushed Rows placed into the buffer because the last flush are lost Do not expect the end of the program to close the cursor and flush the buffer The following example shows a FLUSH statement FLUSH icurs Error Checking FLUSH Statements 1 204 Syntax The SQLCA contains information on the success of each FLUSH statement and the number of rows that are inserted successfully The result of each FLUSH statement is contained in the fields of the sqlca as shown in the following table FLUSH ESQL C ESQL COBOL sqlca sqlcode SQLCODE SQLCODE of SQLCA sqlca sqlerrd 2 SQLERRDJ 3 OF SQLCA When using data buffering with an insert cursor errors are not discovered until the buffer is flushed For example a
106. table Product Name Variable Name ESQL C sqlca sqlcode SQLCODE ESQL COBOL SQLCODE OF SQLCA The following statement causes SQL errors to be ignored each time they are encountered WHENEVER SQLERROR CONTINUE If you do not use any WHENEVER SQLERROR statements in a program the default for WHENEVER SQLERROR is CONTINUE Syntax 1 399 WHENEVER SQLWARNING Keyword If you use the SQLWARNING keyword any SQL statement that generates a warning causes the action indicated by the WHENEVER SQLWARNING state ment to execute If a warning occurs the first field of the SOLAWARN record is set to W The following statement causes a program to stop execution if a warning condition exists WHENEVER SQLWARNING STOP NOT FOUND Keyword If you use the NOT FOUND keyword SELECT and FETCH statements are treated differently from other SQL statements The NOT FOUND keyword check for the following cases e A FETCH statement that attempts to get a row beyond the first or last row in the active set A SELECT statement that returns no rows In both of these cases the sqlcode variable is set to 100 See the figure in SQLERROR Keyword on page 1 399 for the name of the sqlcode variable in each Informix product The following statement calls the no_rows function each time the NOT FOUND condition exists WHENEVER NOT FOUND CALL no_rows ERROR Keyword ERROR is a synonym for SQLERROR GOTO Keyword
107. tables REVOKE Insert delete or update rows of any system catalog table except systables Drop any object regardless of who owns it Create tables views and indexes as well as specify another user as owner of the objects Execute the DROP DATABASE command Execute the START DATABASE and ROLLFORWARD DATABASE commands Warning Although the user informix and DBAs can modify most system catalog tables only user informix can modify systables Informix strongly recommends that you do not update delete or alter any rows in them Modifying the system catalog tables can destroy the integrity of the database References See the GRANT statement in this manual In the Informix Guide to SQL Tutorial see the discussion of privileges and security in Chapter 11 Syntax 1 305 ROLLBACK WORK ROLLBACK WORK Purpose Syntax Usage 1 306 Syntax Use the ROLLBACK WORK statement to cancel a transaction and undo any changes that occurred since the beginning of the transaction ROLLBACK T na WORK The ROLLBACK WORK statement is valid only in databases with transactions In a database that is not ANSI compliant start a transaction with a BEGIN WORK statement You can end a transaction with a COMMIT WORK statement or cancel the transaction with a ROLLBACK WORK statement The ROLLBACK WORK statement restores the database to the state that existed before the transaction began Use the ROLLBACK WORK
108. the temporary tables Alter or drop a table or an index provided the user owns the table or index or has Alter Index or References privileges on the table Grant privileges on a table or view provided the user owns the table or has been given privileges on the table with the WITH GRANT OPTION keyword gives you the ability to extend the structure of the database In addition to the capabilities of the Connect privilege the holder of the Resource privilege can perform the following functions Create new tables Create new indexes Create new procedures in addition to the capabilities of the Resource privilege the holder of the DBA privilege can perform the following functions Grant any database level privilege including DBA privilege to another user Use the NEXT SIZE keyword to alter extent sizes in the system catalog Insert delete or update rows of any system catalog table except systables Drop any object regardless of its owner Create tables views and indexes and specify another user as owner of the objects Execute the DROP DATABASE statement Execute the DROP DISTRIBUTIONS option of the UPDATE STATISTICS statement Execute the START DATABASE and ROLLFORWARD DATABASE statements Syntax 1 233 GRANT 1 234 Syntax User informix has the privilege required to alter tables in the system catalog including the systables table Warning Although the user informix and DBAs can modify most system c
109. the DELETE statement After you indicate cascading deletes when you delete a row from a parent table INFORMIX OnLine Dynamic Server deletes any associated matching rows from the child table Use the ADD CONSTRAINT clause to add a REFERENCES clause with the ON DELETE CASCADE option constraint Syntax 1 23 ALTER TABLE 1 24 Syntax What Happens to Multiple Child Tables When you have a parent table with two child constraints one child with cascading deletes specified and one child without cascading deletes and you attempt to delete a row from the parent table that applies to both child tables then the delete statement fails and no rows are deleted from either the parent or child tables In the previous example the stock table is also parent to the items table However you do not need to add the cascading delete clause to the items table if you are planning to delete items that are not ordered items because the items table is used only for ordered items Locking and Logging During deletes the database server places locks on all qualifying rows of the referenced and referencing tables You must turn logging on when you per form the deletes When logging is turned off in a database even temporarily deletes do not cascade This restriction applies because if logging is turned off you have no way to roll back actions For example if a parent row is deleted and the system crashes before the child rows are deleted the data bas
110. the EXECUTE PROCEDURE statement except it can be used only from within a stored procedure Specifying Arguments If more arguments are in a CALL statement than are expected by the called procedure you receive an error If fewer arguments are specified by a CALL statement than are expected by the called procedure the arguments are said to be missing Missing argu ments are initialized to their corresponding default values if default values were specified See CREATE PROCEDURE on page 1 68 This initialization occurs before the first executable statement in the body of the procedure If arguments are missing and do not have default values they are initialized to the value of UNDEFINED An attempt to use any variable that has the value of UNDEFINED results in an error Procedure arguments are bound to procedure parameters by name or position but not both That is you can use the parameter name syntax for none or all of the arguments specified in one CALL statement Each procedure call in the following example is valid for a procedure that expects character arguments t n and d in that order CALL add_col t customer d integer n newint CALL add_col customer newint integer Subset of SELECT Allowed in a Procedure Argument You can use any SELECT statement as the argument for a procedure as long as it returns exactly one value of the proper type and length See the discus sion of SELECT state
111. the UPDATE STATISTICS statement drops If no columns are specified then all the distributions for that table are removed You must have DBA privileges or be the owner of the table in order to drop distributions The following example shows how to remove distributions for the customer_num column in the customer table UPDATE STATISTICS LOW FOR TABLE customer customer_num DROP DISTRIBUTIONS Creating Distributions for Columns Distributions are a mapping of the data in the column into a carefully chosen set of the column values The contents of the column are examined and divided into bins which represent a percentage of data For example a bin might hold 2 percent of the data 50 bins would hold all the data You can set the width of the bin with the RESOLUTION percent parameter This organization of column values into bins is called the distribution for that column The optimizer examines distributions of columns referenced in a WHERE clause to estimate the effect of a WHERE clause on the data You cannot create distributions for TEXT or BYTE columns If you include a TEXT or BYTE column in an UPDATE STATISTICS statement that specifies MEDIUM or HIGH distributions no distributions are created for those col umns Distributions are constructed for other columns in the list and the statement does not return an error You must have the DBA privilege or be the owner of the table in order to create HIGH or MEDIUM distributio
112. the WHERE CURRENT OF clause of UPDATE or DELETE statement When you modify a row the lock is upgraded to a write lock and remains until the cursor is closed or the transaction ends If you do not modify it the lock may or may not be released when you fetch another row depend ing on the isolation level you have set The lock on an unchanged row is released as soon as another row is fetched unless you are using Repeat able Read isolation see the SET ISOLATION statement on page 1 366 Note You can hold locks on additional rows even when Repeatable Read isolation is not in use or is unavailable Update the row with unchanged data to hold it locked while your program is reading other rows You must evaluate the effect of this technique on performance in the context of your application and you should be aware of the increased potential for deadlock When you use explicit transactions be sure that a row is both fetched and modified within a single transaction that is both the FETCH statement and the subsequent UPDATE or DELETE statement must fall between a BEGIN WORK statement and the next COMMIT WORK statement You cannot set the database isolation level on INFORMIX SE Checking the Result of a FETCH You can check the result of each FETCH statement using the GET DIAGNOSTICS statement You examine the RETURNED_SQLSTATE field of the GET DIAGNOSTICS statement to check if the field contains the value 02000 1 202 Syntax FETCH
113. the number of exceptions returned by the NUMBER field in the Statement clause For example if the NUMBER field returns the number 5 an except_num value of 1 indicates that only the first value of 5 values is requested If multiple errors and warnings are Syntax 1 223 GET DIAGNOSTICS 1 224 Syntax detected by the database server except_num can represent any entry in the returned values ex_var is a host variable that you declared which receives EXCEPTION information about the most recent SQL state ment The ex_var variable receives information for a speci fied exception field name The ex_var variable data type must be the same as that of the requested field When retrieving exception information GET DIAGNOSTICS deposits the values of any of the seven fields into corresponding host variables These fields are located in the diagnostics area and are derived from an exception raised by the most recent SOL statement The host variable data type must be the same as that of the requested field The seven exception information fields are represented by the following keywords ESQL ESQL C COBOL Host Host Field Name Field Field Variable Variable Keyword Data Type Contents Data Type Data Type RETURNED_SQLSTATE Character SQLSTATE char 6 PIC X 5 value CLASS_ORIGIN Character String char 254 PIC X 254 SUBCLASS_ORIGIN Character String char 254 PIC X 254 MESSAGE_TEXT Character String char 254 PIC X
114. the triggered action is completed it effectively executes a SET CONSTRAINTS constr_name IMMEDIATE statement to check the constraints that were deferred This allows you to write triggers so that the triggered action can resolve any constraint violations that the triggering statement creates Consider the following example in which the table child has constraint r1 which references the table parent You define trigger trig1 and activate it with an INSERT statement In the triggered action trig1 checks to see if parent has a row with the value of the current cola in child If not it inserts it CREATE TABLE parent cola INT PRIMARY KEY CREATE TABLE child cola INT REFERENCES parent CONSTRAINT rl CREATE TRIGGER trigl INSERT ON child REFERENCING NEW AS new FOR EACH ROW WHEN SELECT COUNT FROM parent WHERE cola new cola 0 parent row does not exist INSERT INTO parent VALUES new cola When you insert a row to a table that is the child table in a referential constraint the row might not exist in the parent table The database server does not immediately return this error on a triggering statement Instead it allows the triggered action to resolve the constraint violation by inserting the corresponding row into the parent table As shown in the previous example you can check within the triggered action to see whether the parent row exists and if so bypass the insert Syntax 1 131 CREATE
115. the value of variable name and checked to determine whether the value of variable name is still between left expression and right expression If so then the next iteration occurs otherwise the loop is exited or if another range is specified the variable takes on the value of the first element in the next range Specifying Two or More Ranges in a Single FOR Statement The following example shows a statement that traverses a loop forward and backward using different increment values for each direction FOR index_var IN 15 to 21 STEP 2 21 to 15 STEP 3 statement body END FOR Using an Expression List as the Range 2 18 SPL Statements The value of variable name is initialized to the value of the first expression specified In subsequent iterations variable name takes on the value of the next expression When the last expression in the list is used the loop stops The expressions in the IN list are not limited to numeric values as long as no range operators are used in the IN list The following example uses a character expression list FOR c IN hello SELECT name FROM t world vl v2 INSERT INTO t VALUES c END FOR FOR The following FOR statement shows the use of a numeric expression list FOR index IN 15 16 17 18 19 20 21 statement block END FOR Mixing Range and Expression Lists in the Same FOR Statement If variable name is an INT or SMALLINT value you can mix ranges and
116. them that way e Words for which you must supply values are in italics Each diagram begins at the upper left with a keyword and ends at the upper right with a vertical line Between these points you can trace any path that does not stop or back up Each path describes a valid form of the statement Except for separators in loops see page 7 which the path approaches coun terclockwise from the right the path always approaches elements from the left and continues to the right Along a path you may encounter the following elements KEYWORD You must spell a word in uppercase letters exactly as shown however you can use either uppercase or lowercase letters when you enter it Punctuation and mathematical notations are literal symbols that you must enter exactly as shown Single quotes are literal symbols that you must enter as shown variable A word in italics represents a value that you must supply The nature of the value is explained immediately following the diagram unless the variable appears in a box In that case the page number of the detailed explanation follows the variable name ADD Clause A reference in a box represents a subdiagram on the same Bs page if no page number is supplied or on a specified page Imagine that the subdiagram is spliced into the main diagram at this point A code in an icon is a signal warning you that this path is valid only for some products or under certain conditi
117. to all columns because you cannot yet detect whether a column has changed Ifthe triggering UPDATE statement sets a column to the current value you cannot detect the update and therefore the triggered action is CREATE TRIGGER skipped You might want to execute the triggered action even though the value of the column has not changed The Client Server Environment In a database under INFORMIX OnLine Dynamic Server the statements inside the triggered action can affect tables in external databases The follow ing example shows an update trigger on dbserver1 which triggers an update to items on dbserver2 CREATE TRIGGER upd_nt UPDATE ON newtab REFERENCING new AS post FOR EACH ROW UPDATE stores6 dbserver2 items SET quantity post qty WHERE stock_num post stock AND manu_code post mc If a statement from an external database server initiates the trigger however and the triggered action affects tables in an external database the triggered actions fail For example the following combination of triggered action and triggering statement results in an error when the triggering statement executes Triggered action from dbserverl to dbserver3 CREATE TRIGGER upd_nt UPDATE ON newtab REFERENCING new AS post FOR EACH ROW UPDATE stores6 dbserver3 items SET quantity post qty WHERE stock_num post stock AND manu_code post mc Triggering statement from dbserver2 UPDATE stores6 dbserverl ne
118. to have LOW optimization the western database on machine 2 is to have HIGH optimization If the western database were on the same machine as central it would have LOW optimization 1 374 Syntax SET OPTIMIZATION NNECT TO central OPTIMIZATION low LECT catalog description unit_price unit unit_descr manu_name lead_time FROM catalog stock manufact WHERE catalog stock_num stock stock_num AND stock manu_code manufact manu_code AND catalog_num 10025 LOSE DATABASE ONNECT TO western rockie OPTIMIZATION low CT catalog description unit_price unit unit_descr manu_name lead_time FROM catalog stock manufact WHERE catalog stock_num stock stock_num AND stock manu_code manufact manu_code AND catalog_num 10025 UNA fifo A nnaa ET ELE Optimizing Stored Procedures For stored procedures that remain unchanged or are changed only slightly you may want to set the SET OPTIMIZATION statement to HIGH when you create the procedure This stores the best query plans for the procedure Then SET OPTIMIZATION to LOW before you execute the procedure The procedure then uses the optimal query plans and runs at the more cost effective rate References In the Informix Guide to SQL Tutorial see the discussion of optimizing queries in Chapter 13 Syntax 1 375 START DATABASE START DATABASE Purpose Syntax Use the START DATABASE statement with an INFORMIX SE database s
119. to other users When you are satisfied that the database is ready for use release the exclusive lock by issuing the CLOSE DATABASE statement You can open the database with the DATABASE statement You must be working on a database server to issue a ROLLFORWARD DATABASE statement You cannot execute the statement from a client machine ROLLFORWARD DATABASE References See the BEGIN WORK COMMIT WORK CLOSE DATABASE DATABASE and ROLLBACK WORK statements in this manual In the Informix Guide to SQL Tutorial see the discussion of archives and logs in Chapter 4 Syntax 1 309 SELECT SELECT Purpose Use the SELECT statement to query a database Syntax UNION gt UNION ALL Select FROM SELECT Clause Clause p 1 312 p 1 323 INTO Clause p 1 318 RS GROUP BY S Clause p 1 334 HAVING Clause p 1 336 XC INTO TEMP f Clause p 1 341 FOR UPDATE Usage You can query the tables in the current database or in a database that is not current or a database thatis one a different database server than your current database You can query only the current database 1 310 Syntax SELECT The SELECT statement comprises many basic clauses Each clause is described in the following list SELECT clause INTO clause SPL FROM clause WHERE clause GROUP BY clause HAVING clause ORDER BY clause INTO TE
120. turn initiates other triggers Obviously the elapsed time for the triggering data manipulation statement increases as the number of cascading triggers increases See Cas cading Triggers on page 1 130 for more information on triggers initiating other triggers Trigger Name Trigger Name Identifier gt X pi p 1 469 af owner owner is the user name of the owner of the trigger The trigger name follows the same syntax rules as other SQL identifiers See Identifier on page 1 469 Syntax 1 113 CREATE TRIGGER UPDATE Clause UPDATE Clause gt UPDATE T p J OF ic column name key column name is the name of a column that activates the trigger If the trigger event is an UPDATE statement the trigger executes when any column in the triggering column list is updated If you specify one or more triggering column names the column names must belong to the table on which you create the trigger If you do not specify a list of triggering columns the default list consists of all the columns in the table on which you create the trigger If the triggering UPDATE statement updates more than one of the triggering columns in a trigger the trigger executes only once Defining Multiple Update Triggers 1 114 Syntax If you define more than one update trigger event on a table the column lists of the triggers must be mutually exclusive For example of the follo
121. undefined Any Informix error or warning message that is not supported in the ANSI ISO reserved range has an IX class code In addition the subclass code varies depending on the error 1 218 Syntax GET DIAGNOSTICS The following table is a quick reference for interpreting class code values SQLSTATE class code value Outcome 00 Success 01 Success with warning 02 No data found gt 02 Error or warning List of SOLSTATE Codes The following table describes the class codes subclass codes and the meaning of all valid warning and error codes associated with the SQLSTATE error status code Class Subclass Meaning 00 000 Success 01 000 Success with warning 01 002 Disconnect error Transaction rolled back 01 003 Null value eliminated in set function 01 004 String data right truncation 01 005 Insufficient item descriptor areas 01 006 Privilege not revoked 02 000 No data found 07 000 Dynamic SQL error 07 001 Using clause does not match dynamic parameters 07 002 Using clause does not match target specifications 07 003 Cursor specification cannot be executed 07 004 Using clause is required for dynamic parameters 07 005 Prepared statement is not a cursor specification 07 006 Restricted data type attribute violation 07 008 Invalid descriptor count 07 009 Invalid descriptor index 08 000 Connection exception 08 001 Server rejected the connection 08 002 Connection name in us
122. use in CREATE TABLE 1 885 with IN keyword 1 327S DATE using as a default value 1 19S 1 898 INTERVAL in Condition segment 1 405S in expression 1 436S 1 441S segment 1 490S syntax 1 491S syntax in INSERT 1 250S using as default value 1 195 1 895 Number in Condition segment 1 405S in expression 1 436S 1 439S segment 1 493S syntax 1 493S syntax in INSERT 1 250S with IN keyword 1 409S LOAD statement DELIMITER clause 1 258S input formats for data 1 256S INSERT INTO clause 1 258S loading VARCHAR TEXT or BYTE data types 1 257S specifying field delimiter with DBDELIMITER 4 18R specifying the table to load into 1 2585 syntax 1 255S the LOAD FROM file 1 256S Loading data from a command file into a table 5 20R Local loopback 12 9T Local server 12 5T LOCK MODE keywords syntax in ALTER TABLE 1 155 in CREATE TABLE 1 108S use in ALTER TABLE 1 335 in CREATE TABLE 1 108S LOCK TABLE statement in databases with transactions 1 261S in databases without transactions 1 262S locking a table explicitly 7 7T syntax 1 260S Locking and concurrency 4 27T and integrity 7 3T deadlock 7 14T description of 7 5T during delete 1 159S inserts 1 249S updates 1 152S5 1 385S granularity 7 6T in OnLine 1 5R in SE 1 6R lock duration 7 8T lock mode 7 13T not wait 7 14T wait 7 13T locks released at end of transaction 7 18T mode 1 5R overriding row level 1 261S releasing with COMMIT WORK 1 43S releasing with ROLLBACK WORK 1 306S scope
123. used in the GET DESCRIPTOR statement must be declared in the BEGIN DECLARE SECTION of an ESQL program See your SQL API manual for specifics Using the COUNT Keyword Use the COUNT keyword to determine how many values are described into the system descriptor area The following INFORMIX ESQL C example shows how to use a GET DESCRIPTOR statement with a host variable to determine how many values are described in the system descriptor area called desc1 main exec sql begin declare section int h_type h_count exec sql end declare section exec sql allocate descriptor descl with max occurrences 20 This section of program would prepare a SELECT or INSERT statement into the s_id statement id x7 exec sql describe s_id using sql descriptor descl exec sql get descriptor descl h_count count VALUE Clause 1 212 Syntax Use the VALUE clause to obtain information about a described column or expression or to retrieve values returned by the database server x O GET DESCRIPTOR The item number must be greater than zero and less than the number of occurrences specified when the system descriptor area was allocated using ALLOCATE DESCRIPTOR Using the VALUE Clause After a Describe After you describe a SELECT EXECUTE PROCEDURE or INSERT statement the characteristics of each column or expression in the select list of the SELECT statement the characteristics of the values returned by the EXEC
124. values stock_no manu_code descr u_price unit u_desc The insert cursor simply inserts rows of data it cannot be used for fetching data When an insert cursor is opened a buffer is created in memory to hold a block of rows The buffer receives rows of data as the program executes PUT statements The rows are written to disk only when the buffer is full You can use the CLOSE FLUSH or COMMIT WORK statement to flush the buffer when it is less than full This topic is discussed further under the PUT and CLOSE statements You must close an insert cursor to insert any buffered rows into the database before the program ends You can lose data if you do not close the cursor properly Using an Insert Cursor with Hold If you associate a hold cursor with an INSERT statement you can break a long series of PUT statements into smaller sets of PUT statements by using transac tions Instead of waiting for the PUT statements to fill the buffer and trigger an automatic write to the database you can execute a COMMIT WORK state ment to flush the row buffer If you use a hold cursor the COMMIT WORK statement commits the inserted rows but leaves the cursor open for further Syntax 1 157 DECLARE inserts This method can be desirable when you are inserting a large number of rows because pending uncommitted work consumes database server resources References See the CLOSE DELETE EXECUTE PROCEDURE FETCH FREE INSERT OPEN PREPA
125. with DROP INDEX 1 174S duplicate entries 10 16T 10 22T effect of physical order 13 27T in GROUP BY 13 10T in ORDER BY 13 10T locks table 7 7T managing 10 19T naming conventions 1 419S 1 469S 1 484S 1 505S optimizer 13 29T optimizer uses 13 9T 13 10T 13 26T ordering columns in composite 13 31T performance effects 13 18T sharing with constraints 1 86S sorting with NLS 1 15R time cost of 10 20T updating affects 13 31T utility to test or repair 13 31T when not used by optimizer 13 32T 13 33T 13 35T with temporary tables 1 343S INDEX keyword syntax in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S Index Name segment syntax 1 4195 1 495S use 1 504S Index privilege 1 236S 11 8T INDEXES FOR keywords in INFO statement 1 242S Indexes with dbload utility 5 21R INDICATOR field setting with SET DESCRIPTOR 1 358S INDICATOR keyword in SELECT 1 3195 1 320S 1 3215 1 432S Indicator variable definition of 5 15T in EXECUTE 1 186S in expression 1 467S in SELECT 1 319S 1 3208 1 3215 1 4325 using non English characters in 1 22R INFO statement displaying privileges and status 1 2425 displaying tables columns and indexes 1 2415 syntax 1 241S informix environment configuration file 4 4R privileges associated with user 1 234S Informix extension checking specifying with DBANSIWARN 4 15R INFORMIX 4GL 12 5T detecting null value 5 16T example of dynamic SQL 11 13T indicator variable not used
126. with PREVIOUS retrieves the previous row in the active set FIRST retrieves the first row in the active set LAST retrieves the last row in the active set CURRENT retrieves the current row in the active set the same row as returned by the preceding FETCH statement from the scroll cursor RELATIVE retrieves the nth row relative to the current cursor position in the active set where n is supplied by row position A nega tive value indicates the nth row prior to the current cursor position If row position is zero the current row is fetched ABSOLUTE retrieves the nth row in the active set where n is supplied by row position Absolute row positions are numbered from one 1 196 Syntax FETCH The following INFORMIX ESQL C examples illustrate the FETCH statement exec sql fetch previous q_curs into orders exec sql fetch last q_curs into orders exec sql fetch relative 10 q_curs into orders printf Which row scanf Sd row_num exec sql fetch absolute row_num q_curs into orders Row Numbers The row numbers used with the ABSOLUTE keyword are valid only while the cursor is open Do not confuse them with rowid values A rowid value is based on the position of a row in its table and remains valid until the table is rebuilt A row number for a FETCH statement is based on the position of the row in the active set of the cursor the next time the cursor is opened different rows may be selected H
127. you can use the full database server and database name See Database Name on page 1 421 for more information The DROP DATABASE statement does not remove the database directory if it includes any files other than those created for database tables and their indexes You can specify the full pathname of the database in quotes as shown in the following example DROP DATABASE u training stores6 You cannot use a ROLLBACK WORK statement to undo a DROP DATABASE statement If you roll back a transaction that contains a DROP DATABASE statement the database is not re created and you do not receive an error message You can specify a database that is not in your local directory or DBPATH by SI putting the full operating system file in a variable for the database name LET db_var u training stores6 DROP DATABASE db_var References See the CREATE DATABASE and CLOSE DATABASE statements in this manual Syntax 1 173 DROP INDEX DROP INDEX Syntax Usage 1 174 Syntax Use the DROP INDEX statement to remove an index Index EEJ bRoP INDEX _ Mame p 1 484 You must be the owner of the index or have the DBA privilege to use the DROP INDEX statement The following example drops the index o_num_ix owned by joed The stores6 database must be the current database DROP INDEX stores6 joed o_num_ix You cannot use the DROP INDEX statement on a column or columns
128. you roll back a transaction that contains a CREATE TABLE state ment the table remains and you do not receive an error message Using the CREATE TABLE statement outside the CREATE SCHEMA statement generates warnings if you use the ansi flag or set DBANSIWARN Using the CREATE TABLE statement generates warnings if you use the ansi flag or set DBANSIWARN Defining Constraints When you create a table several elements must be defined For example the table and columns within that table must have unique names Also every table column must have at least a data type associated with it You can also optionally place several constraints on a given column For example you can indicate that the column has a specific default value or that data entered into the column must be checked to meet a specific data requirement Putting a constraint on a column is similar to putting an index on a column using the CREATE INDEX statement However if you use constraints instead of indexes you also can implement data integrity constraints and turn effec tive checking off and on For information on data integrity constraints see Chapter 3 of the Informix Guide to SQL Tutorial For information on effective checking see the SET CONSTRAINTS statement on page 1 349 Note In a database without logging the only constraint checking mode available is detached Detached checking means that constraint checking is performed on a row by row basis Syntax 1 8
129. you specify user as the default value for a column the column must be of type CHAR VARCHAR NCHAR or NVARCHAR and it must be at least eight characters long In an ANSI compliant database if you do not use quotes around the owner name the name of the table owner is stored as uppercase letters If you use the USER keyword as part of a condition you must be sure that the way the user name is stored agrees with the values that are returned by the USER function with respect to case SITENAME and DBSERVERNAME Functions 1 438 Syntax The SITENAME and DBSERVERNAME functions return the database server name as defined in the ONCOMFIG file for the INFORMIX OnLine Dynamic Server installation on which the current database resides or as specified in the INFORMIXSERVER environment variable The two function names Expression SITENAME and DBSERVERNAME are synonymous You can use the DBSERVERNAME function to determine the location of a table to put infor mation into a table or to extract information from a table You can insert DBSERVERNAME into a simple character field or use it as a default value for a column If you specify DBSERVERNAME as a default value for a column the column must be of type CHAR VARCHAR NCHAR or NVARCHAR and must be at least 18 characters long In the following example the first statement returns the name of the database server on which the customer table resides Because the query is not restricted with a WHERE
130. 0S Loo controlled 2 165 creating and exiting in SPL 14 23T exiting using RAISE exception 14 32T indefinite with WHILE 2 465 Loopback local 12 9T LOW keyword 1 374S M Machine notes Intro 9R Intro 11S 6T Mandatory entity in relationship 8 9T Many to many relationship 8 9T 8 11T 8 26T Mapping files for non standard code sets 5 5R MATCHES keyword syntax in Condition segment 1 405S use in Condition segment 1 409S in SELECT 1 328S with NLS 2 42T used to test for equality in WHERE clause 2 29T wildcard characters 1 329S MATCHES relational operator in WHERE clause 2 37T MAX function as aggregate function 2 53T syntax in expression 1 462S use in expression 1 464S MDY function as time function 2 56T syntax in expression 1 454S Memory allocating for a system sqlda structure 1 98 shared 12 7T Message files error messages Intro 9R Intro 115 7T setting LANG for NLS 4 49R specifying subdirectory for NLS 1 22R specifying subdirectory with DBLANG 4 19R MIN function as aggregate function 2 53T syntax in expression 1 462S use in expression 1 464S Minus sign arithmetic operator 1 431S MINUTE keyword syntax in DATETIME data type 1 428S in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 14R 1 491S Mirror See Disk mirroring MOD function syntax in expression 1 444S use in expression 1 446S MODE ANSI keywords ANSI compliant database 1 15T ANSI compliant logging 9
131. 1 196S First normal form 8 29T Fixed point 9 10T FLOAT data type changing data types 3 23R description of 3 12R 9 9T syntax 1 425S using as default value 1 195 1 895 Floating point 9 9T FLUSH statement count of rows inserted 6 11T syntax 1 204S with concatenation operator 1 4325 writing rows to buffer 6 10T FOR EACH ROW action SELECT statement in 1 117S triggered action list 1 116S FOR EACH ROW action See also FOREACH keyword FOR keyword in CONTINUE 2 65 in CREATE AUDIT 1 555 in CREATE SYNONYM 1 805 in EXIT 2 145 for locating temporary tables 1 100S FOR statement looping in a stored procedure 14 23T specifying multiple ranges 2 18S syntax 2 16S using expression lists 2 18S using increments 2 175 FOR TABLE keywords in UPDATE STATISTICS 1 393S FOR UPDATE keywords conflicts with ORDER BY 6 8T not needed in ANSI compliant database 6 16T relation to UPDATE 1 390S specific columns 6 16T syntax in DECLARE 1 145S use in DECLARE 1 1485 1 152S 1 155S in SELECT 1 340S with column list 1 153S FOREACH keyword in CONTINUE statement 2 65 in EXIT 2 14S FOREACH keyword See also FOR EACH ROW action FOREACH statement looping in a stored procedure 14 23T syntax 2 20S Foreign characters using NLS 1 14R Foreign key 1 225 1 935 1 945 4 19T See also Referential constraint FOREIGN KEY keywords in ALTER TABLE 1 295 in CREATE TABLE 1 928 Format for crtcmap mapping file 5 6R specifying for DATE value with DBDATE 4 16R specifyi
132. 1 217 GRANT 1 231 INFO 1 241 INSERT 1 245 LOAD 1 255 LOCK TABLE 1 260 OPEN 1 263 OUTPUT 1 271 PREPARE 1 273 PUT 1 284 RECOVER TABLE 1 292 RENAME COLUMN 1 294 RENAME TABLE 1 296 REPAIR TABLE 1 299 REVOKE 1 300 ROLLBACK WORK 1 306 ROLLFORWARD DATABASE 1 308 SELECT 1 310 SET CONNECTION 1 346 SET CONSTRAINTS 1 349 SET DEBUG FILE TO 1 351 SET DESCRIPTOR 1 353 SET EXPLAIN 1 360 SET ISOLATION 1 366 SET LOCK MODE 1 370 SET LOG 1 372 SET OPTIMIZATION 1 374 START DATABASE 1 376 UNLOAD 1 378 UNLOCK TABLE 1 381 UPDATE 1 383 UPDATE STATISTICS 1 392 WHENEVER 1 398 Segments 1 403 Condition 1 404 Constraint Name 1 419 Database Name 1 421 Data Type 1 424 DATETIME Field Qualifier 1 428 Expression 1 430 Identifier 1 469 Index Name 1 484 INTERVAL Field Qualifier 1 485 Literal DATETIME 1 487 Literal Interval 1 490 Literal Number 1 493 Procedure Name 1 495 Quoted String 1 497 Relational Operator 1 500 Synonym Name 1 504 Table Name 1 506 View Name 1 510 Chapter 2 SPL Statements Chapter Overview 2 3 CALL 2 3 CONTINUE 2 6 DEFINE 2 7 EXIT 2 14 Table of Contents ix FOR 2 16 FOREACH 2 20 IF 2 24 LET 2 28 ON EXCEPTION 2 31 RAISE EXCEPTION 2 36 RETURN 2 38 SYSTEM 2 40 TRACE 2 42 WHILE 2 46 Index x Table of Contents Introduction Introduction Informix Products That UseSQL 3 Products Included in This Manual 3 Other Useful Documentation 4 How to Use This Manual 5 Typographical Conventions 5
133. 1 400 Syntax Use the GOTO clause to transfer control to the statement identified by the label The GO TO keyword is a synonym for GOTO WHENEVER The following example shows that the WHENEVER statement in INFORMIX ESQLI C code transfers control to the statement labeled missing each time the NOT FOUND condition occurs query_data EXEC SQL WHENEVER NOT FOUND GO TO missing EXEC SQL FETCH lname INTO lname missing printf No Customers Found If your program contains more than one function you might need to redefine the error condition For example assume the module contains three func tions and the first function includes a WHENEVER GOTO statement and a corresponding labeled statement When compilation moves from the first function to the following function the error condition still refers to the label however the label is no longer defined If the INFORMIX ESQL C compiler reads an SQL statement and you have not redefined the error condition for example to WHENEVER SQLERROR CONTINUE an error results from the compiler You can either reset the error condition by issuing another WHENEVER statement you can put a labeled statement with the same label name in each function or you can use the CALL clause to call a separate function CALL Clause Use the CALL clause to transfer program control to the named function Do not include parentheses after the function name You cannot pass variables to
134. 1 8T 11 28T DELETE REFERENCING clause and FOR EACH ROW section 1 121S correlation name 1 119S syntax 1 119S DELETE statement all rows of table 4 4T and end of data 6 14T applied to view 11 24T as triggering statement 1 1125 cascading 1 160S coordinated deletes 6 6T count of rows 6 4T CURRENT OF clause 1 161S description of 4 4T embedded 5 6T 6 3T to 6 8T in trigger event 1 111S in triggered action 1 122S number of rows 5 12T preparing 5 30T privilege for 1 235S 11 6T 11 8T syntax 1 159S time to update indexes 10 20T transactions with 6 5T using subquery 4 6T WHERE clause restricted 4 6T with Condition segment 1 404S with cursor 1 152S 6 7T with select for update 1 340S within a transaction 1 159S Delete cascading See Cascading deletes Delimiter for DATETIME values 3 9R for INTERVAL values 3 15R for LOAD input file 1 258S specifying with UNLOAD 1 380S Delimiter form of FILE and INSERT statements 5 24R DELIMITER keyword in LOAD 1 258S in UNLOAD 1 380S Demonstration database copying Intro 10R Intro 135 8T installation script Intro 9R Intro 12S 7T map of A 6R overview Intro 9R Intro 12S 7T structure of tables A 2R tables in A 2R to A 6R See also stores6 database Denormalizing 10 26T Derived data introduced for performance 10 30T produced by view 11 20T DESC keyword 1 338S syntax in CREATE INDEX 1 63S in SELECT 1 337S use in CREATE INDEX 1 665 in SELECT 1 338S Desc
135. 10 S es WITHOUT PIPE program HEADINGS filename is the name of the operating system file in which you want to store the results of the query program is the name of the program where you want the query results piped or otherwise sent You can send the results of a query to an operating system file by specifying the full pathname for the file If the file already exists the output overwrites the current contents as shown in the following example OUTPUT TO usr april queryl SELECT FROM cust_calls WHERE call_code L You can display the results of a query without column headings by using the WITHOUT HEADINGS keywords as shown in the following example OUTPUT TO usr april queryl WITHOUT HEADINGS SELECT FROM cust_calls WHERE call_code L Syntax 1 271 OUTPUT You also can use the keyword PIPE to send the query results to another program as shown in the following example OUTPUT TO PIPE more SELECT customer_num call_dtime call_code FROM cust_calls References See the SELECT and UNLOAD statements in this manual 1 272 Syntax PREPARE PREPARE Purpose Syntax Usage Use the PREPARE statement to parse validate and generate an execution plan for SQL statements in INFORMIX ESQL program at run time Quoted R PREPARE stajement FROM String plete statement variable id variable name statement id is an SQL statement identifier The statement id must confor
136. 13 EXIT EXIT Purpose Use the EXIT statement to stop the execution of a FOR FOREACH or WHILE loop Syntax EXIT FOR a WHILE FOREACH Usage The EXIT statement causes the innermost loop of the indicated type WHILE FOR or FOREACH to terminate Execution resumes at the first statement outside the loop If the EXIT statement cannot find the identified loop it fails Used outside all loops the EXIT statement generates errors 2 14 SPL Statements EXIT In the following example an EXIT FOR statement is used In the FOR loop when j becomes 6 the IF condition i 5 in the WHILE loop is true The FOR loop stops executing and it continues at the next statement outside the FOR loop in this case the END PROCEDURE statement In the following example the procedure finishes when j equals 6 CREATE PROC EDURE ex_cont_ex DEFINE i s j INT FOR j IF END LET END END FOR END PROCEDURE 3 WHILE i gt 0 i 1 TO 20 j gt 10 THEN CONTINUE FOR IF i s 7 OF LET issi IF i 5 THEN EXIT FOR END IF WHILE SPL Statements 2 15 FOR FOR Purpose Syntax variable Use the FOR statement to initiate a controlled definite loop in cases where you want to guarantee termination of the loop The FOR statement uses expressions or range operators to establish a finite number of iterations for a loop FOR name IN s left express
137. 145 When the program opens the cursor the associated SELECT INSERT or EXECUTE PROCEDURE statement is passed to the database server which begins execution When the program has retrieved or inserted all the rows it needs the cursor should be closed using the CLOSE statement The specific actions taken by the database server differ depending on whether the cursor is associated with a SELECT statement or an INSERT statement The SELECT INSERT or EXECUTE PROCEDURE statement associated with a cursor is prepared implicitly by the OPEN statement The total number of epgprepared objects and open cursors allowed in one program at any time is limited by the available memory You can use the FREE statement to free the cursor to release the database server resources You receive an error code if you open a cursor that is already open Opening a Select Cursor 1 264 Syntax When you open either a select cursor or an update cursor the SELECT statement is passed to the database server along with any values specified in the USING clause If the statement was previously prepared the statement passed to the database server when it was prepared The database server processes the query to the point of locating or constructing the first row of the active set Because this is the first time that the database server sees the query it is the time when many errors are detected The database server does not actually return the first row of data
138. 1S WITH CHECK keywords syntax in CREATE VIEW 1 136S use in CREATE VIEW 1 138S WITH CHECK OPTION keywords 11 25T WITH GRANT keywords syntax in GRANT 1 231S use in GRANT 1 237S WITH HOLD keywords declaring a hold cursor 7 19T 10 34T syntax in DECLARE 1 145S use in DECLARE 1 1508 1 157S WITH keyword syntax in CREATE DATABASE 1 57S WITH LISTING IN keywords warnings in a stored procedure 14 8T WITH LOG IN keywords syntax in START DATABASE 1 376S WITH MAX keywords relationship with COUNT field 1 354S WITH NO LOG keywords syntax in CREATE TABLE 1 848 in SELECT 1 341S use in CREATE TABLE 1 1045 in SELECT 1 343S WITH NO LOG keywords syntax in START DATABASE 1 376S WITH RESUME keywords in RETURN 2 395 WITHOUT HEADINGS keywords in the OUTPUT statement 1 271S WORM drive 12 6T Write once read many times device See WORM drive Writing a dbload command file in character position form 5 31R in delimiter form 5 26R X X Open and Informix implementation of NLS 1 15R setting NLS environment variables 4 43R setting the LC_COLLATE category 4 50R setting the LC_CTYPE category 4 51R setting the LC_MONETARY category 4 52R setting the LC_NUMERIC category 4 53R setting the LC_TIME category 4 53R specifications icon for Intro 8S X Open mode FETCH statement 1 195S GET DESCRIPTOR 1 2135 SET DESCRIPTOR statement 1 357S X Open specification of NLS 1 15R Y YEAR function as time function 2 56T syntax in expression 1 454S use
139. 25 SYSTEM statement syntax 2 40S Index 43 44 Index T Table adding a constraint 1 295 alias in SELECT 1 323S ANSI compliant naming 1 507S bottleneck 10 35T candidate keys defined 8 23T changing the data type of a column 3 23R checking with the CHECK TABLE statement 1 375 composite key defined 8 23T contained in one dbspace 10 5T creating a synonym for 1 80S a table 1 845 9 24T a temporary table 1 100S dedicated device for 10 6T description of 1 11T dropping a constraint 1 325 a synonym 1 177S a table 1 179S engine response to locked table 1 370S extent sizes of 10 8T fixed length rows 10 13T in mirrored storage 10 6T in relational model 1 11T 8 20T interleaved dbspaces 10 10T joins in Condition segment 1 331S loading data with the LOAD statement 1 255S lock 7 7T locking changing mode 1 335 with ALTER INDEX 1 135 with LOCK TABLE 1 260S logging 1 104S multiple access arms for 10 7T names 12 16T names synonyms 12 17T naming conventions 1 845 1 470S 1 507S naming with NLS 1 15R optimizing queries 1 3945 ownership 11 7T primary key in 8 22T primary key defined 8 22T relation to dbspace 10 6T repairing with REPAIR TABLE statement 1 299S represents an entity 8 22T restoring with audit trail 1 2925 structure in stores6 database A 2R system catalog tables 2 11R to 2 33R unlocking 1 381S variable length rows 10 14T See also ALTER TABLE statement See also CREATE TABLE statement See also Join See
140. 28T needed to create a view 1 239S 11 27T to drop an index 1 1745 to modify data 1 236S 4 15T on a synonym 1 805 on a view 1 137S 11 28T on stored procedures 14 13T overview 1 8T Resource 1 233S 11 7T 13 34T Select 11 8T 11 10T 11 27T Update 1 236S 11 8T 11 10T 11 28T when privileges conflict 1 232S with DBA privileged procedures 14 13T with owner privileged procedures 14 13T See also Database level privilege See also Table level privilege PRIVILEGES FOR keywords in INFO statement 1 243S PRIVILEGES keyword syntax in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S Procedure cursor opening 1 265S reopening 1 2675 procedure cursor 1 148S Procedure name conflict with function name 1 495S naming conventions 1 495S Procedure stored See Stored procedure Processing distributed 12 8T Projection described 2 7T Project description of 1 13T Promotable lock 1 152S 7 6T 7 9T PSORT_DBTEMP environment variable 4 40R PSORT_NPROCS environment variable 4 41R PUBLIC keyword privilege granted to all users 11 6T syntax in GRANT 1 231S in REVOKE 1 300S use in GRANT 1 234S in REVOKE 1 302S PUT statement constant data with 6 11T count of rows inserted 6 11T impact on trigger 1 1125 sends returned data to buffer 6 10T source of row values 1 285S syntax 1 284S use in transactions 1 285S with concatenation operator 1 432S with FLUSH 1 285S Q Qualifier field for DATETIME 3 8R 1 4285 1 488
141. 3S NLS 1 16T NLS versus non NLS 1 20R NLS accessing 1 20R opening in exclusive mode 1 1425 optimizing queries 1 394S populating new tables 9 27T relation to dbspace 10 5T relational defined 1 11T remote 1 4225 restoring 1 308S server 1 8T 1 16T server definition of 1 16T stopping logging on 1 376S stores6 Intro 9R Intro 12S 7T stores6 description of A 1R table names 12 16T See also Database Name segment Database Administrator DBA 1 233S 11 7T Database application See Application Database lock 7 6T Database management system 12 4T Database Name segment database outside DBPATH 1 423S for remote database 1 422S naming conventions 1 421S naming with variable 1 4235 syntax 1 421S using quotes slashes 1 423S Database server choosing OnLine or SE 1 3R configuration 12 15T definition of 1 16T effect of server type on available data types 1 4R isolation level 1 6R locking 1 5R rolling back transactions 1 4R SQL statements supported 1 7R system catalog tables 1 7R transaction logging 1 5R local 12 5T NLS versus non NLS 1 20R remote 12 8T specifying default for connection 4 36R DATABASE statement determining database type 1 140S exclusive mode 1 142S 7 6T for database outside DBPATH 1 141S locking 7 6T specifying current database 1 140S SQLAWARN after 1 1415S 5 12T syntax 1 140S using with program variables 1 141S See also Database Name segment Database level privilege description of 1 232S 4 15T gran
142. 4 18R writing a command file in character position form 5 31R writing a command file in delimiter form 5 26R DBMONEY environment variable 4 20R 9 12T DBMS See Database management system DBNLS environment variable 1 16R 4 48R DBPATH environment variable 4 21R 1 1415 1 4235 12 14T DBPRINT environment variable 4 24R DBREMOTECMD environment variable 4 25R Directory extension dbs extension 1 101S dbs extension Intro 11R 1 585 1 141S Index 13 14 Index dbschema utility create schema for a database 5 34R description of 5 33R options obtaining privilege schema 5 36R obtaining synonym schema 5 35R specifying a table view or procedure 5 37R owner conventions 5 35R use of 9 26T DBSERVERNAME function returning servername 1 4385 use in ALTER TABLE 1 185 in CREATE TABLE 1 888 in expression 1 438S in SELECT 2 63T 2 65T 3 20T dbspace definition of 10 4T division into extents 10 8T for temporary tables 10 6T mirrored 10 5T multiple access arms in 10 7T on dedicated device 10 6T relation to tblspace 10 7T root 10 5T selecting with CREATE DATABASE 1 57S 9 22T DBSPACETEMFP environment variable 4 26R 1 100S DBTEMP environment variable 4 27R DBTIME environment variable 4 27R DBUPSPACE environment variable 4 30R DDL statements summary 1 5S Deadlock detection 1 371S 7 14T DEALLOCATE DESCRIPTOR statement syntax 1 143S with concatenation operator 1 432S DEC data type See DECIMAL data type DECIMAL data type chang
143. 4 55R and TERMCAP environment variable 4 56R and TERMINFO environment variable 4 56R terminfo directory and TERMINFO environment variable 4 56R selecting with INFORMIXTERM 4 39R TERMINFO environment variable 4 56R TEXT data type choosing location for 10 18T description of 3 21R 9 17T disk storage for 10 4T estimating disk space for 10 17T inserting values 3 21R requirements for LOAD statement 1 257S restrictions with aggregate functions 3 21R with GROUP BY 3 21R 3 7T with IN clause 3 21R with LIKE or MATCHES 3 21R 2 37T with ORDER BY 3 21R with relational expression 2 29T selecting a column 3 22R syntax 1 425S use in Boolean expression 3 21R used for performance 10 27T with control characters 3 21R with LENGTH function 2 64T with stored procedures 2 95 2 135 Text editor specifying with DBEDIT 4 18R TEXT value displaying 2 11T Third normal form 8 32T Time function restrictions with GROUP BY 1 334S use in SELECT 1 314S Time representing with NLS 1 15R TO CLUSTER keywords in ALTER INDEX 1 12S TO keyword in expression 1 462S in GRANT 1 231S TODAY function syntax in Condition segment 1 405S in expression 1 436S in INSERT 1 250S use in ALTER TABLE 1 188 in constant expression 1 4395 2 63T 4 8T in CREATE TABLE 1 888 in INSERT 1 252S TP XA See Transaction manager TRACE command output from 15 14T TRACE statement debugging a stored procedure 14 11T syntax 2 425 Transaction and CREATE DATABASE 1 60S
144. 5 CREATE TABLE You can define constraints at either the column or table level If you choose to define constraints at the column level you cannot have multiple column con straints In other words the constraint created at the column level only can apply to a single column If you choose to define constraints at the table level you can apply constraints to single or multiple columns At either level single column constraints are treated the same way Whenever you place a data restriction on a column a constraint is created automatically You have the option of specifying a name for the constraint If you choose not to specify a name for the constraint the database server creates a default constraint name for you automatically Limits on Constraint Definitions You can include up to 16 columns inclusive in a list of columns for a unique primary key or referential constraint The total length of all columns cannot exceed 255 bytes You can use up to 8 columns inclusive in an INFORMIX SE list of columns The total length of all columns cannot exceed 120 bytes Adding or Dropping Constraints Once you have used the CREATE TABLE statement to place constraints on a column or set of columns you must use the ALTER TABLE statement to add or drop the constraint from the column or composite column list Enforcing Primary Key Unique and Referential Constraints 1 86 Syntax Primary key unique and referential constraints are im
145. 5 to a stored procedure 14 25T Parameterizing a statement with SQL identifiers 1 279S Parent child relationship 1 215 1 945 Parts explosion 5 26T PATH environment variable 4 54R 12 14T Pathname including in SQLEXEC 4 42R specifying with DBPATH 4 21R specifying with PATH 4 54R Percent sign wildcard in Condition segment 1 410S PERFORM keyword in the WHENEVER statement 1 398S Performance adding indexes 13 34T assigning table to dedicated disk 10 6T bottleneck tables 10 35T buffered log 9 22T clustered index 10 25T depends on concurrency 7 3T disk access 13 14T 13 17T 13 34T disk access by rowid 13 18T disk arm motion 10 8T disk latency 13 17T dropping indexes to speed modifications 10 24T duplicate keys slow modifications 10 22T effect of BLOB location 10 18T correlated subquery 13 32T filter expression 13 23T 13 32T 13 33T index damage 13 31T indexes 10 21T to 10 22T 13 26T regular expressions 13 32T table size 13 19T 13 34T updates 13 31T filter selectivity 13 30T hot spots finding 13 7T improved by specifying optimization level 13 36T improved with temporary table 13 36T improving 13 27T increasing with stored procedures 14 4T index time during modification 10 20T interleaved dbspaces 10 10T journal updates 10 33T measurement 13 6T multiple access arms per table 10 7T network access 13 20T nonsequential access 13 18T optimizing 13 3T to 13 42T references to other books 13 3T reorganizing a dbs
146. 64T VARCHAR value displaying 2 11T Variable default values in SPL 2 1185 2 125 define in SPL 2 75 global in SPL 2 10S 14 17T in SPL 14 16T local in SPL 2 125 14 17T scope of SPL variable 2 8S unknown values in IF 2 25S with same name as a keyword 14 19T View creating a view 1 136S 11 20T creating synonym for 1 80S deleting rows in 11 24T description of 11 19T display description with dbschema 34R dropped when basis is dropped 11 22T dropping 1 183S effect of changing basis 11 23T effect on performance 13 33T inserting rows in 11 25T modifying 11 23T to 11 27T naming with NLS 1 15R null inserted in unexposed columns 11 25T privilege when accessing 11 28T privilege when creating 1 137S privileges 11 27T to 11 30T privileges with GRANT 1 239S produces duplicate rows 11 22T restrictions with UNION operator 1 3445 system catalog table 2 33R updatable 1 139S updating 1 384S updating duplicate rows 11 25T using CHECK OPTION 11 25T virtual column 1 1375S 11 24T with SELECT notation 1 136S View Name segment 1 510S Ww WAIT keyword in the SET LOCK MODE statement 1 370S WARNING keyword in the WHENEVER statement 1 398S Warnings with stored procedures at compile time 14 8T WEEKDAY function as time function 2 56T 2 60T syntax in expression 1 454S use in expression 1 456S WHEN condition in triggered action 1 122S restrictions 1 122S use of 1 122S WHENEVER statement syntax and use 1 398S WHERE clause sub
147. 86S restrictions with GROUP BY 1 334S syntax 1 436S See also Expression segment See also Literal Number Constraint adding with ALTER TABLE 1 298 1 865 cardinality 8 9T checking 1 131S defining domains 9 3T definition of 1 85S dropping with ALTER TABLE 1 325 1 865 enforcing 1 86S modifying a column that has constraints 1 27S number of columns allowed 1 86S 1 925 optimizer uses 13 9T privileges needed to create 1 31S rules for unique constraints 1 30S setting checking mode 1 349S specifying at table level 1 925 with DROP INDEX 1 1745 See also Primary key constraint See also Referential constraint See also Unique constraint CONSTRAINT keyword in ALTER TABLE 1 298 in CREATE TABLE 1 918 Contention for bottleneck tables 10 35T for disk access arms 10 7T reducing 10 32T 10 35T CONTINUE keyword in the WHENEVER statement 1 398S 1 402S CONTINUE statement exiting a loop 14 23T syntax 2 6S Conventions example code Intro 8R Intro 10S 5T for naming tables 1 845 syntax Intro 5S typographical Intro 5R Intro 5S 5T Converting data types 3 23R Coordinated deletes 6 6T Correlated subquery definition of 1 413S 3 32T restriction with cascading deletes 4 22T Correlation name and stored procedures 1 125S in COUNT DISTINCT clause 1 125S in DELETE REFERENCING clause 1 119S in GROUP BY clause 1 125S in INSERT REFERENCING clause 1 118S in SET clause 1 125S in stored procedure 1 128S in UPDATE REFERENCING clause 1 120S ne
148. 999 years The following examples show several forms of INTERVAL qualifiers YEAR 5 TO MONTH DAY 5 TO FRACTION 2 DAY TO DAY FRACTION TO FRACTION 4 References In the Informix Guide to SQL Reference for information about using INTERVAL data in arithmetic and relational operations see Chapter 3 1 486 Syntax Literal DATETIME Literal DATETIME Purpose Use a literal DATETIME segment as a DATETIME value The literal DATETIME segment is used in the following statements and segments INSERT statement SELECT statement UPDATE statement Condition segment e Expression segment Syntax 1 487 Literal DATETIME Syntax DATETIME p gt DATETIME g Field Qualifier p 1 Numeric Date gt WYN 7 KN gt A mo N N gt ad S A space KN gt A hh s N mi A mi N S A SS an Ng Gy J yyyy is the year in up to four digits If you use two digits 19 is assumed as the first part of the year as in 1993 mo is the month in two digits dd is the day in up to two digits space is literally a space made by pressing the spacebar hh is the hour in up to two digits mi is the minute in up to two digits ss is the second in up to two digits f is the fraction of a second in up to five digits depending on 1 488 Syntax the precision given to the fractional portion in the INTERVAL qualifier Literal DATETIME Usage T
149. AGE_TEXT messlen MESSAGE_LENGTH printf SQLSTATE s n SQLSTATE printf CLASS s n class printf SUBCLASS s n subclass printf TEXT s n message printf MESSLEN d n messlen if warning return exit 1 GRANT GRANT Purpose Use the GRANT statement to specify access privileges for a database or for the tables and views in a database Syntax GRANT ga TO PUBLIC le user Table Table N Level ON Name TO PUBLIC Privileges p 1 506 p 1 235 View Name user p 1 510 i user Synonym Name p 1 504 Procedure EXECUTE ON Name p 1 495 of J X WITH GRANT OPTION AS grantor p grantor identifies the user who is granting the privilege to user As the current user you are the default grantor user names the user or users who receive privileges Granting privileges to PUBLIC extends a privilege to the class of all authorized users both current and future If you use quotes user appears exactly as typed ZG In an ANSI compliant database if you do not use quotes around user the name of the user is stored as uppercase letters Syntax 1 231 GRANT Usage A GRANT statement can extend user privileges but cannot limit existing privileges Later GRANT statements do not affect privileges already granted to a user When database level privileges collide with table level privileges the mor
150. AL Types If you set the TYPE field for a DATETIME or INTERVAL value you can set the DATA field as a literal DATETIME or INTERVAL or as a character string If you use a character string you must set the LENGTH field to the encoded qualifier value To determine the encoded qualifiers fora DATETIME or INTERVAL character string use the datetime and interval macros in the datetime h header file If you set DATA to a host variable of DATETIME or INTERVAL you do not need to set LENGTH explicitly to the encoded qualifier integer To determine the encoded qualifiers fora DATETIME or INTERVAL character string use the ECO IQU routine Setting the INDICATOR Field If you want to put a null value into the system descriptor area set the INDICATOR field to 1 and do not set the DATA field If you set the INDICATOR field to 0 indicating that the data is not null you must set the DATA field SET DESCRIPTOR Setting the ITYPE Field The ITYPE field expects an integer constant that indicates the data type of your indicator variable Use the same set of constants as for the TYPE field The constants are listed in Figure 1 11 Modifying Values Set by the DESCRIBE Statement You can modify the contents of a system descriptor area after it is set using a DESCRIBE statement After you use a DESCRIBE statement on SELECT or an INSERT statement you must check to determine whether the TYPE field is set to either 11 or 12 indicating a TEXT or B
151. ANSI compliant database effects 1 11R committing with COMMIT WORK 1 43S cursors closed at end 7 18T description of 4 22T example with DELETE 6 5T global 12 21T locks held to end of 7 9T locks released at end 7 8T 7 18T logging 1 376S recovering transactions 1 308S Index 45 46 Index rolling back 1 4R 1 306S scroll cursor and data consistency 1 369S starting with BEGIN WORK 1 35S stopping logging 1 376S transaction log 4 24T 4 26T transaction log required 9 22T use signalled in SQLAWARN 5 12T using cursors in 1 155S Transaction logging ANSI compliant database effects 1 12R buffered 9 22T effect on database server type 1 5R establishing with CREATE DATABASE 9 21T OnLine methods of 9 22T renaming log 1 377S stopping 1 377S turning off for faster loading 9 28T turning off not possible 9 24T Transaction log contents of 4 25T Transaction manager 12 11T Transfer of database files 5 19R Transitive dependency 8 32T Trigger creating 15 4T definition of 15 3T in client server environment 1 133S number on a table 1 112S preventing overriding 1 132S when to use 15 3T Trigger event definition of 1 111S 15 5T example of 15 5T in CREATE TRIGGER statement 1 1115 INSERT 1 119S privileges on 1 113S with cursor statement 1 112S Trigger name assigning 15 5T syntax 1 113S Triggered action action on triggering table 1 127S anyone can use 1 1295 BEFORE and AFTER 15 7T cascading 1 118S clause 1 1215 action statements 1 1225
152. ASE UNLOAD WHENEVER You can use a SELECT statement only if you use the INTO TEMP clause to put the results of the SELECT statement into a temporary table SPL Statements 2 27 LET LET Purpose Syntax J variable LET Use the LET statement to assign values to variables You also can use the LET statement to call a procedure within a procedure and assign the returned values to variables name Usage 2 28 SPL Statements Procedure Expression 2 3 Name p 1 430 called ra p 1 495 variable J Expression J p 1 430 called variable is a procedure variable of the called procedure Procedure arguments are bound to procedure parameters by name or position but not both That is you can use called variable syntax for none or all the arguments specified in one LET statement variable name is a procedure variable If you assign a value to a single variable it is called a simple assignment if you assign values to two or more variables it is called a compound assignment At run time the value of the SPL expression is computed first The resulting value is converted to variable name type if possible and the assignment takes place If conversion is not possible an error occurs and the value of variable name is undefined A compound assignment assigns multiple expressions to multiple variables The count and type of expressions in the e
153. ATCHES with a wildcard in several SELECT statements The first SELECT statement finds all stock items that are some kind of ball The second SELECT statement finds all company names that con tain an asterisk The backslash is used as the standard escape character for the wildcard asterisk The third statement uses the ESCAPE option with the MATCHES condition to retrieve rows from the customer table in which the company column includes an asterisk The z character is used as an escape character for the wildcard asterisk SELECT stock_num manu_code FROM stock WHERE description MATCHES ball SELECT FROM customer WHERE company MATCHES SELECT FROM customer WHERE company MATCHES z ESCAPE Gl N With NLS enabled the following example selects data containing foreign characters from columns in a table named with foreign characters The val ues that meet the criteria for the MATCHES condition in the WHERE clause vary depending on environment variable settings SELECT num ro nom pr nom FROM abonn s WHERE nom MATCHES E P ORDER BY nom IN Subquery For a complete description of the IN subquery see page 1 408 With the IN subquery more than one row can be returned but only one column can be returned The following example shows the use of an IN subquery in a SELECT statement SELECT DISTINCT customer_num FROM orders WHERE order_num NOT IN SELECT o
154. BASE CONNECT CREATE AUDIT CREATE DATABASE CREATE INDEX CREATE OPTICAL CLUSTER CREATE PROCEDURE FROM CREATE SYNONYM CREATE TRIGGER DATABASE DESCRIBE DISCONNECT DROP AUDIT DROP DATABASE DROP INDEX DROP OPTICAL CLUSTER DROP PROCEDURE DROP SYNONYM DROP TABLE DROP TRIGGER DROP VIEW EXECUTE EXECUTE PROCEDURE Statements That are Extensions to the ANSI Standard FREE INFO LOAD LOCK TABLE OUTPUT PREPARE PUT RECOVER TABLE RELEASE RENAME COLUMN RENAME TABLE RESERVE REVOKE ROLLFORWARD DATABASE SET CONNECTION SET CONSTRAINTS SET DEBUG FILE TO SET EXPLAIN SET ISOLATION SET LOCK MODE SET LOG SET MOUNTING TIMEOUT SET OPTIMIZATION START DATABASE UNLOAD UNLOCK TABLE UPDATE STATISTICS ALLOCATE DESCRIPTOR ALLOCATE DESCRIPTOR Purpose Syntax Usage Use the ALLOCATE DESCRIPTOR statement to allocate memory for a system descriptor area that is identified by a descriptor or descriptor variable Use it to create a place in memory to hold information obtained by a DESCRIBE statement or to hold information about the WHERE clause of a statement Bega ALLOCATE descriptor DESCRIPTOR P yar WITH MAX descriptor occurrences variable Be occurrences variable descriptor is a quoted string that identifies the system descriptor area The descriptor must conform to the same rules as any identifier as described in the Identifier segment on page 1 469 descriptor variable is an embedded v
155. CT statement use the DISTINCT keyword in the SELECT clause as described on page 1 312 Reference In the Informix Guide to SQL Tutorial see the discussion of outer joins in Chapter 3 Syntax 1 345 SET CONNECTION SET CONNECTION Purpose The SET CONNECTION statement reestablishes a connection between an application and a database server and makes the connection current Syntax E C i connection E CO SET CONNECTION name l conn_nm variable DEFAULT connection is a quoted string that identifies the database environment name to which you are reestablishing a connection It is the Usage 1 346 Syntax connection name assigned by the CONNECT statement when the initial connection was made conn_nm is an ESQL C or ESQL COBOL character type host variable variable that identifies the database environment to which you are reestablishing a connection The value of conn_nm variable is the connection name created by the CONNECT statement when the initial connection was made The SET CONNECTION statement makes the specified dormant connection the current one You can reestablish only a dormant connection A dormant connection is a connection that has been established but is not current If another connection is current when the statement executes that connection becomes dormant A dormant connection has a connection context associated with it The connection context includes the name of the current user and al
156. DATABASE statement or a PREPARE statement for one of these statements and an EXECUTE statement to open a database Syntax 1 49 CONNECT Specifying a Database Only The dbname option and the pathname dbname option for SE establishes connections to the default server or to another database server in the DBPATH variable It also locates and opens the named database This is also true of the db_env variable option if it specifies only a database name See Locating the Database on page 1 50 for the order in which an application connects to different servers to locate a database Locating the Database 1 50 Syntax How a database is located and opened depends on both of the following factors Whether you specify a database server name in the database environment expression Whether the database server is INFORMIX OnLine Dynamic Server or INFORMIX SE Server and Database Specified If you specify both a database server and a database in the CONNECT statement your application connects to the database server which locates and opens the database If the database server is an OnLine database server it locates the database using parameters specified in the ONCONFIG configuration file The database server searches the directory that you supply If you do not supply a directory path it searches in the current directory if the server is local the login directory if the server is remote or the DBPATH environment varia
157. DAY keyword syntax in DATETIME data type 1 4285 in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 14R 1 491S DBA keyword in GRANT 1 233S in REVOKE 1 303S DB Access creating database with 5 34T 9 26T UNLOAD statement 9 28T DBANSIWARN environment variable 4 15R 1 785 1 85S 1 137S 5 10T DBAPICODE environment variable 1 16R 4 47R relation to crtcmap utility 5 5R DBA privileged procedure 14 13T DBA See Database Administrator DBDATE environment variable 4 16R 4 8T 9 13T DBDELIMITER environment variable 4 18R 1 258S DBEDIT environment variable 4 18R dbexport utility description of 5 8R destination options 5 10R Interrupt key 5 9R specifying field delimiter with DBDELIMITER 4 18R unloading a database 5 8R using with NLS 5 12R dbimport utility create options 5 16R creating a database 5 14R description of 5 13R input file location options 5 15R Interrupt key 5 14R using with NLS 5 13R 5 18R DBINFO function syntax in expression 1 448S use in expression 1 4485 DBLANG environment variable 4 19R dbload utility creating a command file 5 23R description of 5 19R INSERT statement compared to SQL INSERT statement 5 30R Interrupt key 5 21R loading data from a command file 5 20R loading data into a table 9 28T 10 12T options bad row limits 5 23R batch size 5 22R command file syntax check 5 21R load start point 5 22R specifying field delimiter with DBDELIMITER
158. DELETE provides the ability to delete rows SELECT provides the ability to display data obtained from a SELECT statement UPDATE provides the ability to change column values INDEX provides the ability to create permanent indexes You must have the Resource privilege to take advantage of the Index privilege Any user with the Connect privilege can create indexes on temporary tables ALTER provides the ability to modify column data types or to add or delete columns REFERENCES provides the ability to reference columns in referential constraints You must have the Resource privilege to take advantage of the References privilege However you can add a referential constraint during an ALTER TABLE state ment This method does not require that you have the Resource privilege on the database Revoke the References privilege to disallow cascading deletes ALL provides all the preceding privileges The PRIVILEGES keyword is optional REVOKE The following example revokes the Index and Alter privileges from all users for the customer table these privileges are then granted specifically to user maty REVOKE INDEX ALTER ON customer FROM PUBLIC GRANT INDEX ALTER ON customer TO mary Because you cannot revoke access on specific columns when you revoke the Select Update or References privilege from a user you revoke the privilege for all columns in the table You must use a GRANT statement to specifically regrant any column spe
159. DROP AUDIT RECOVER TABLE SELECT UNLOAD UPDATE FLUSH OPEN PUT FREE GET DESCRIPTOR PREPARE SET DESCRIPTOR SET ISOLATION SET LOCK MODE UNLOCK TABLE REPAIR TABLE ROLLBACK WORK ROLLFORWARD DATABASE SET CONSTRAINTS SET LOG START DATABASE Query Optimization Information Statements SET EXPLAIN SET OPTIMIZATION Stored Procedure Statements EXECUTE PROCEDURE Auxiliary Statements INFO OUTPUT 1 6 Syntax UPDATE STATISTICS SET DEBUG FILE TO WHENEVER GET DIAGNOSTICS SQL Statements Client Server Connection Statements CONNECT DISCONNECT SET CONNECTION INFORMIX OnLine Optical Statements ALTER OPTICAL CLUSTER CREATE OPTICAL CLUSTER DROP OPTICAL CLUSTER RELEASE RESERVE SET MOUNTING TIMING Note INFORMIX OnLine Optical statements are shown and described in INFORMIX OnLine Optical User Manual ANSI Compliance and Extensions The following lists show ANSI compliant statements and extensions to the ANSI standard ANSI Compliant Statements ALLOCATE DESCRIPTOR CLOSE COMMIT WORK CREATE VIEW DEALLOCATE DESCRIPTOR DELETE FROM EXECUTE IMMEDIATE GET DESCRIPTOR GET DIAGNOSTICS INSERT OPEN ROLLBACK WORK SET DESCRIPTOR UPDATE ANSI Compliant Statements with Informix Extensions CREATE SCHEMA AUTHORIZATION CREATE TABLE DECLARE Syntax 1 7 SQL Statements FETCH SELECT WHENEVER ALTER INDEX ALTER OPTICAL CLUSTER ALTER TABLE BEGIN WORK CHECK TABLE CLOSE DATA
160. DROP TRIGGER statement is illegal inside the stored procedure procl INSERT INTO orders EXECUTE PROCEDURE procl vala valb You cannot use a ROLLBACK WORK statement to undo a DROP TRIGGER statement If you roll back a transaction that contains a DROP TRIGGER state ment the trigger is not re created and you do not receive an error message Syntax 1 181 DROP TRIGGER References See the CREATE PROCEDURE statement in this manual for more information about a stored procedure that is called within a data manipulation statement For more information about triggers see the CREATE TRIGGER statement in this manual 1 182 Syntax DROP VIEW DROP VIEW Purpose Use the DROP VIEW statement to remove a view from the database Syntax View DROP VIEW Name p 1 510 Synonym Name p 1 504 Usage You must own the view or have the DBA privilege to use the DROP VIEW statement When you drop view name you also drop all views that have been defined in terms of view name You can determine which if any views depend on another view by querying the sysdepend system catalog table The following statement drops the view named cust1 DROP VIEW custl You cannot use a ROLLBACK WORK statement to undo a DROP VIEW state ment If you roll back a transaction that contains a DROP VIEW statement the view is not re created and you do not receive an error message References See the CREATE V
161. E DELETE ROLLBACK WORK DROP INDEX SET CONSTRAINT DROP OPTICAL UPDATE SQL statements not allowed in a procedure that is called in a data manipulation statement For example if you use the following INSERT statement the execution of the called procedure dup_name is restricted CREATE PROCEDURE sp_insert INSERT INTO q customer VALUES SELECT FROM customer WHERE dup_name lname 2 END PROCEDURE In the preceding example dup_name cannot execute the statements listed in Figure 1 3 However if dup_name is called within a statement that is not an INSERT UPDATE SELECT or DELETE statement namely EXECUTE PROCEDURE dup_name can execute the statements listed in Figure 1 3 Note that you can use the BEGIN WORK and COMMIT WORK statements in procedures You can start a transaction finish a transaction or start and finish a transaction in a procedure If you start a transaction in a procedure that is executed remotely you must finish the transaction before the procedure exits CREATE PROCEDURE References See the CREATE PROCEDURE FROM DROP PROCEDURE GRANT EXECUTE PROCEDURE PREPARE UPDATE STATISTICS and REVOKE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of creating and using stored procedures in Chapter 14 Syntax 1 75 CREATE PROCEDURE FROM CREATE PROCEDURE FROM Purpose Use the CREATE PROCEDURE FROM statement to create a procedure The ac
162. E STATISTICS statement INFORMIX OnLine Dynamic Server recalculates the data in the systables syscolumns sysin dexes and sysdistrib system catalog tables The optimizer uses this data to determine the best execution path for queries The database server does not update this statistical data automatically Statistics are updated only when you issue an UPDATE STATISTICS statement Using the UPDATE STATISTICS statement also updates the optimized execution plans for procedures in the sysprocplan system catalog table Each time a procedure executes the database server reoptimizes its execution plan if any of the objects referenced in the procedure have changed The UPDATE STATISTICS statement requires a current database If you omit the FOR TABLE or FOR PROCEDURE clauses statistics are updated for every table and procedure in the current database including the system tables If you use UPDATE STATISTICS FOR TABLE without a table name the statistics for all tables including temporary tables in the current database are updated If you use the FOR PROCEDURE keyword without a procedure name the statistics for all stored procedures in the current database are updated You cannot update the statistics used by the optimizer for a table or procedure that is external to the current database UPDATE STATISTICS with INFORMIX SE does not update rows in the sysindexes table when you issue an UPDATE STATISTICS statement INFORMIX SE recalculates o
163. E clause that selects all rows in the table DB Access gives no prompt and deletes all rows DELETE Deleting and the WHERE Clause If you delete from a table in an ANSI compliant database using a WHERE clause and no rows are found you can detect this condition using the GET DIAGNOSTICS statement The RETURNED_SQLSTATE field of GET DIAGNOS TICS contains the value 02000 In a database that is not ANSI compliant no error is returned If you delete from a table using a WHERE clause in a multistatement prepare in either ANSI databases and databases that are not ANSI compliant and no rows are found you receive a GET DIAGNOSTICS RETURNED_SQLSTATE field value of 02000 For additional information about the SOLSTATE code see the GET DIAGNOSTICS statement in this manual You can also use SOLCODE of sqlca to determine the same results See the Informix Guide to SQL Tutorial for further information about SQLCODE of sqlca CURRENT OF Clause To use the CURRENT OF clause you must have previously used the DECLARE statement with the FOR UPDATE clause to announce the cursor name If you use the CURRENT OF clause the DELETE statement removes the row of the active set at the current position of the cursor After the deletion no current row exists you cannot use the cursor to delete or update a row until you reposition the cursor with a FETCH statement All select cursors are potentially update cursors in ANSI compliant datab
164. E data INSERT INTO cust_calls call_dtime VALUES 1992 5 4 10 12 11 INSERT INTO manufact lead_time VALUES 14 The format of the value in the quoted string must exactly match the format specified by the qualifiers of the column For the first case in the preceding example call_dtime must be defined with the qualifiers YEAR TO MINUTE for the INSERT statement to be valid LIKE and MATCHES in a Condition Quoted strings with the LIKE or MATCHES keyword in a condition can include wildcard characters See the Condition segment beginning on page 1 404 for a complete description of how to use wildcard characters Inserting Values as Quoted Strings 1 498 Syntax If you are inserting a value that is a quoted string you must adhere to the following conventions e Enclose CHAR VARCHAR NCHAR NVARCHAR DATE DATETIME and INTERVAL values in quotation marks Set DATE values in the mm dd yyy format or in the format specified by DBSET if set e You cannot insert strings longer than 256 bytes Quoted String Numbers with decimal values must contain a decimal point You cannot use a comma as a decimal indicator e You cannot precede MONEY data with a dollar sign or include commas e You can include NULL as a placeholder only if the column accepts null values Syntax 1 499 Relational Operator Relational Operator Purpose Use a relational operator to compare two expressions quantitativ
165. EATE TABLE mytab unique INTEGER fails The workaround shown in the following example uses two SQL statements The first statement creates the column mycol the second renames the column mycol to unique CREATE TABLE mytab mycol INTEGER RENAME COLUMN mytab mycol TO unique Syntax 1 473 Identifier The workaround in the following example also uses two SQL statements The first statement creates the column mycol the second alters the table adds the column unique and drops the column mycol CREATE TABLE mytab mycol INTEGER ALTER TABLE mytab ADD unique integer ROP mycol iw Using INTERVAL or DATETIME as a Column Name The examples in this section show workarounds for using the keyword INTERVAL or DATETIME as a column name in a SELECT statement Using interval as a column name causes the following example to fail because the database server interprets interval as a keyword and expects it to be followed by an INTERVAL qualifier SELECT interval FROM mytab fails The workaround in the following example removes ambiguity by specifying a table name with the column name SELECT mytab interval FROM mytab The workaround in the following example includes an owner name with the table name SELECT josh mytab interval FROM josh mytab Using rowid as a Column Name 1 474 Syntax Every table has a virtual column named rowid To avoid ambiguity you cann
166. ECT statement If a synonym refers to a table or view in the same database the synonym is automatically dropped if you drop the referenced table or view You cannot create a synonym for a synonym in the same database The name of a synonym is qualified by the owner of the synonym owner synonym The identifier owner synonym must be unique among all the synonyms tables temporary tables and views in the database You must specify owner when you refer to a synonym owned by another user The following example shows the convention CREATE SYNONYM emp FOR accting employee CREATE SYNONYM You cannot use a ROLLBACK WORK statement to undo a CREATE SYNONYM statement If you roll back a transaction that contains a CREATE SYNONYM statement the synonym remains and you do not receive an error message You can create a synonym for any table or view on any database on your database server Use the owner convention if the table is part of an ANSI compliant database The following example shows a synonym for a table outside the current database It assumes that you are working on the same database server that contains the payables database CREATE SYNONYM mysum FOR payables jean summary You can create a synonym for any table or view that exists on any networked database server as well as on the database server that contains your current database The database server that holds the table must be on line when you create the s
167. ECT statement returns only one row The following example shows a singleton SELECT statement in INFORMIX ESQL C exec sql select fname lname company_name into p_fname p_lname p_coname where customer_num 101 INTO Clause with Indicator Variables SELECT You should use an indicator variable if the possibility exists that data returned from the SELECT statement is NULL See your SQL API product manual for more information about indicator variables INTO Clause with Cursors If the SELECT statement returns more than one row you must use a cursor to FETCH the rows individually You can put the INTO clause in the FETCH statement rather than in the SELECT statement but you cannot put it in both The following INFORMIX ESQL C code examples show using the INTO clause in the SELECT and the FETCH statement respectively exec sql declare q_curs cursor select lname company for into p_lname p_company from customer exec sql open q_curs while SQLCODE 0 exec sql fetch q_curs exec sql close q_curs INFORMIX ESQL C exec sql declare q_curs cursor select lname company from customer exec sql open q curs while SQLCODE 0 exec sql fetch q_curs into exec sql close q_curs for p_lname p_company INFORMIX ESQL C Syntax 1 319 SELECT Preparing a SELECT INTO Query 1 320 Syntax You cannot prepare a query that has an INTO clause You can prepare the query without th
168. ELECT bonus FROM mgr WHERE eno mgr Ina triggered action an unqualified column name from the triggering table refers to the current column value but only when the triggered statement is valid independent of the triggered action Qualified Versus Unqualified Value 1 126 Syntax The following table summarizes the value retrieved when you use the column name qualified by the old correlation name and the column name qualified by the new correlation name Trigger Event old col new col INSERT no value error inserted value UPDATE original value current value N column updated UPDATE original value current value U column not updated DELETE original value no value error Refer to the following key when reading the table original value before the triggering statement current value after the triggering statement N cannot be changed by triggered action U can be updated by triggered statements value may be different than original value because of preceding triggered actions Outside a FOR EACH ROW triggered action list you cannot qualify a column from the triggering table with either the old correlation name or the new cor relation name thus it always refers to the current value in the database CREATE TRIGGER Action on the Triggering Table You cannot reference the triggering table in any triggered SQL statement with the following exceptions e The trigger event is UPDATE and the t
169. ETE statement contains the clause WHERE CURRENT OF each update or delete activates the complete trigger Note that this behavior is different from what occurs when a trigger ing statement does not use a cursor and updates multiple rows In this case the set of triggered actions executes only once See Action Clause on page 1 116 for more information on the execution of triggered actions CREATE TRIGGER Privileges on the Trigger Event You must have the appropriate Insert Delete or Update privilege on the triggering table to execute the INSERT DELETE or UPDATE statement that is the trigger event The triggering statement might still fail however if you do not have the privileges necessary to execute one of the SQL statements in the action clause When the triggered actions are executed the database server checks your privileges for each SQL statement in the trigger definition as if the statement were being executed independently of the trigger See Privi leges to Execute Triggered Actions on page 1 129 for information on the privileges you need to execute a trigger Impact of Triggers The INSERT DELETE and UPDATE statements that initiate triggers might appear to execute slowly because they activate additional SQL statements and the user might not know that other actions are occurring The execution time for a triggering data manipulation statement depends on the complexity of the triggered action and whether it in
170. EXCEPTION statement that traps for an exception of 99999 should be in the code RAISE EXCEPTION FOREACH SELECT cl INTO a FROM t IF a lt 0 THEN RAISE EXCEPTION 99999 emergency exit END IF END FOREACH See the ON EXCEPTION statement for more information about scope and compatibility of exceptions SPL Statements 2 37 RETURN RETURN Purpose Syntax Usage 2 38 SPL Statements Use the RETURN statement to designate the values that are returned by the procedure to the calling module RETURN Ra RESUME ye Expression p 1 430 The RETURN statement returns zero or more values to the calling process All the RETURN statements in the procedure must be consistent with the RETURNING clause of the CREATE PROCEDURE statement that defined the procedure The number and type of values in the RETURN statement if any must match in number and type the types listed in the RETURNING clause of the CREATE PROCEDURE statement You can choose to return no values even if you specify one or more values in the RETURNING clause If you use a RETURN statement without any expressions but the calling procedure or pro gram expects one or more return values it is equivalent to returning the expected number of null values to the calling program In the following example the procedure includes two acceptable RETURN statements A program that calls this procedure should check if no values are returned and act
171. EXT columns foreign keys Syntax 1 93 CREATE TABLE The REFERENCES Clause REFERENCES Clause Tabl REFERENCES Nama p p 1 506 a 1 94 Syntax Lea XN ON DELETE CASCADE You can use the REFERENCES clause to reference a column or set of columns If you are defining the REFERENCES clause at the column level you can reference only a single column The table referenced in the REFERENCES clause must reside in the same database as the created table Referenced and Referencing Column Requirements In a referential relationship the referenced column is a column or set of columns within a table that uniquely identifies each row in the table In other words the referenced column or set of columns must be a unique or primary key constraint If the referenced columns do not meet this criteria the database server returns an error Unlike a referenced column the referencing column or set of columns can contain null and duplicate values However every non null value in the ref erencing columns must match a value in the referenced columns When a referencing column meets this criteria it is called a foreign key The relationship between referenced and referencing columns is called a par ent child relationship where the parent is the referenced column or primary key and the child is the referencing column or foreign key This parent child relationship is established through a referential constraint
172. FAULT Option on page 1 46 and The Implicit Connection with DATABASE Statements on page 1 46 for more information When a Transaction is Active If the current connection has an uncommitted transaction when the SET CONNECTION statement executes the following conditions apply e If the current connection was established using the WITH CONCURRENT TRANSACTION clause the application can switch to a different connection e If the current connection was established without the WITH CONCURRENT TRANSACTION clause the application cannot switch to a different connection the SET CONNECTION statements returns an error and the transaction in the current connection continues to be active The application must commit or roll back the active transaction before switching the connection Syntax 1 347 SET CONNECTION Current Connection is to pre Version 6 0 INFORMIX OnLine Dynamic Server If the current connection is to a pre Version 6 0 OnLine database server when the SET CONNECTION statement executes the following conditions apply e If the current connection was established using the WITH CONCURRENT TRANSACTION clause the application can switch to a different connec tion e If the current connection was established without the WITH CONCURRENT TRANSACTION clause the application cannot switch to a different connection the SET CONNECTION statement returns an error The application must use the CLOSE DATABASE statement to close the
173. Functions __4 p 1 455 Trigonometric S unctions p 1 458 The following examples show function expressions EXTEND call_dtime YEAR TO SECOND DY 12 7 1900 cur_yr DATE 365 2 LENGTH abc LENGTH pvar HEX customer_num HEX LENGTH 123 TAN radians ABS 32 EXP 4 3 MOD 10 3 Syntax 1 443 Expression Algebraic Functions An algebraic function takes one or more argument as shown in the following diagram Algebraic Functions ABS numeric expression gt p gt gt N MOD dividend divisor N Pow base exponent A N ROOT e radicand j 4 index we KN _ _ Expression J ROUND p 1 430 rounding factor o N SQRT integer expression A TRUNC Expression p p 1 430 truncating factor 0 base represents a number raised to a power It is any numeric expression that evaluates to a real number dividend represents the value to be divided It is any real number or expression divisor represents the value by which the dividend is to be divided It can be any real number except zero exponent represents the power to which a value is to be raised It is any real number 1 444 Syntax index integer expression numeric expression radicand rounding factor truncating factor ABS Function Expression represents the type of root you are returning I
174. GNOSTICS statement for information about how to get the SQLSTATE value and how to use the GET DIAGNOSTICS statement to interpret the SQLSTATE value If the insert is not successful the number of successfully inserted rows is stored in sqlerrd Any buffered rows following the last successfully inserted row are discarded Because in this case the CLOSE statement failed the Syntax 1 39 CLOSE cursor is not closed A second CLOSE statement can be successful because no buffered rows exist A subsequent OPEN statement also should be successful because the OPEN statement performs a successful implicit close An example of a situation in which a CLOSE statement fails and produces this setting is if insufficient disk space is available for some of the rows to be inserted Using End of Transaction to Close a Cursor The COMMIT WORK and ROLLBACK WORK statements close all cursors except those declared with hold It is better to close all cursors explicitly how ever For select or procedure cursors this simply makes the intent of the pro gram clear It also helps to avoid a logic error if the WITH HOLD clause is later added to the declaration of a cursor For an insert cursor it is important to use the CLOSE statement explicitly so you can test the error code Following the COMMIT WORK statement SQL CODE reflects the result of the COMMIT statement not the result of closing cursors If you use a COMMIT WORK statement without first using a CL
175. H string from customer Selecting Function Expressions A function expression is an expression that uses a function that is evaluated for each row in the query All function expressions require arguments This set of expressions contains the time functions and the length function when they are used with a column name as an argument SELECT The following examples show function expressions within a select list SELECT EXTEND res_dtime YEAR TO SECOND FROM cust_calls SELECT LENGTH fname LENGTH lname FROM customer SELECT HEX order_num FROM orders SELECT MONTH order_date FROM orders Selecting Aggregate Expressions An aggregate function returns one value for a set of queried rows The aggregate functions take on values that depend on the set of rows returned by the WHERE clause of the SELECT statement In the absence of a WHERE clause the aggregate functions take on values that depend on all the rows formed by the FROM clause The following examples show aggregate functions in a select list SELECT SUM total_price FROM items WHERE order_num 1013 SELECT COUNT FROM orders WHERE order_num 1001 SELECT MAX LENGTH fname LENGTH lname FROM customer Selecting Stored Procedure Expressions Stored procedures extend the range of functions available to you and allow you to perform a subquery on each row you select The following example calls the get_orders procedure for each
176. I 124 or the value of the DBDELIMITER environment variable if set filename is a quoted string constant that specifies the name of a file Rows retrieved in the SELECT statement are written to this file Usage To use the UNLOAD statement you must have the Select privilege on all columns selected in the SELECT statement For information on database level and table level privileges see the GRANT statement on page 1 231 The SELECT statement can consist of a literal SELECT statement or the name of a character variable that contains a SELECT statement See the SELECT statement on page 1 310 UNLOAD TO File The UNLOAD TO file contains the selected rows retrieved from the table 1 378 Syntax UNLOAD The following table shows types of data and their output format for an UNLOAD statement in DB Access Data Type character date MONEY NULL number time Output Format If a character field contains the delimiter character Informix products automatically escape it with a backslash to prevent interpretation as a special character If you use a LOAD statement to insert the rows into a table backslashes are automatically stripped Trailing blanks are automatically clipped DATE values are represented as mm dd yyyy where mm is the month January 1 and so on dd is the day and yyyy is the year unless the DBDATE environment variable has been set and another format is specified You can specify a different date format w
177. IEW and DROP TABLE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of views in Chapter 11 Syntax 1 183 EXECUTE EXECUTE Purpose Syntax statement id statement AS EXECUTE 1 184 Syntax Use the EXECUTE statement to run a previously prepared statement or set of statements id variable descriptor descriptor variable USING variable Y name gt indicator variable INDICATOR nadicator variable descriptor A SQL DESCRIPTOR i descriptor variable cS DESCRIPTOR is a quoted string that identifies the system descriptor area that was previously allocated sqida pointer o is an embedded variable name that identifies the system descriptor area that was previously allocated indicator variableis a program variable that receives a return code if null data sqlda pointer statement id statement id variable is placed in the corresponding data variable is an INFORMIX ESQL C pointer to an sqlda structure that describes the undefined values in the prepared statement is an SQL statement identifier defined in a previous PREPARE statement in the same module is an embedded variable name that identifies the SQL state ment defined in a previous PREPARE statement in the same module Usage EXECUTE variable name is an INFORMIX ESQL host variable to be substituted as a value for a question mark placeholder require
178. IME 10 BYTE 11 TEXT 12 VARCHAR 13 INTERVAL 14 NCHAR 15 NVARCHAR 16 TYPE codes The following example shows how you can set the TYPE field in ESOL C main exec sql begin declare section int count itemno type length exec sql end declare section exec sql allocate descriptor descl with max 5 exec sql set descriptor descl value 2 type 5 type 2 itemno 3 exec sql set descriptor descl value itemno type type x O SET DESCRIPTOR If you do not compile using the xopen option the regular Informix SQL code is assigned for TYPE You must be careful not to mix normal and X Open modes because errors can result For example if a particular type is not defined under X Open mode but is defined under normal mode executing a SET DESCRIPTOR statement can result in an error Setting the TYPE Field in X Open Programs In X Open mode you must use the X Open set of integer codes for the data type in the TYPE field The X Open codes for data types are shown in the following table SQL Data Type Integer Value HAR LOAT C SMAI INTEGER F DECIMAL WA oO Br If you use the ILENGTH IDATA or ITYPE fields in a SET DESCRIPTOR statement a warning message appears The warning indicates that these fields are not standard X Open fields for a system descriptor area Setting the DATA Field When you set the DATA field you must provide the appropriate type of data charact
179. ING SQL DESCRIPTOR Clause 1 268 Syntax You also can associate input values from a system descriptor area The keywords USING SQL DESCRIPTOR indicate the use of a system descriptor This allows you to associate input values from a system descriptor area and open a cursor If a system descriptor area is used the count value specifies the number of input values that are described in occurrences of sqlvar This number must correspond to the number of dynamic parameters in the prepared statement The value of count must be less than or equal to the value of occurrences specified when the system descriptor area was allocated OPEN For further information refer to the discussion of the system descriptor area in your INFORMIX ESQL product manual The following examples show the OPEN USING SQL DESCRIPTOR clause and INFORMIX ESQL C and INFORMIX ESQL COBOL respectively exec sql open selcurs using sql descriptor descl INFORMIX ESQL C EXEC SQL OPEN SEL_CURS USING SQL DESCRIPTOR DESC1 END EXEC INFORMIX ESQL COBOL USING DESCRIPTOR Clause E C You can pass parameters for a prepared statement in the form of an sqlda pointer structure which lists the data type and memory location of one or more values to replace question mark placeholders For further informa tion refer to the sqlda discussion in the INFORMIX ESQL C Programmer s Manual The following example shows the OPEN USING DESCRIPTOR clause in INFORMI
180. ING clause of a subquery You cannot use an aggregate function in a comparison condition that is part of a WHERE clause in a DELETE SELECT or UPDATE statement unless the aggregate is on a correlated column originating from a parent query and the WHERE clause is within a subquery that is within a HAVING clause NOT Operator Option If you preface a condition with the keyword NOT the test is true only if the condition that the NOT qualifies is false If the condition qualified by the NOT is unknown uses a null in the determination the NOT operator has no effect The following truth table shows the effect of NOT The letter T represents a true condition F represents a false condition and represents an unknown condition Unknown values occur when part of an expression that uses an arithmetic operator is null NOT T F F T 2 Comparison Conditions Boolean Expressions Five kinds of comparison conditions exist Relational Operator BETWEEN IN IS NULL and LIKE and MATCHES Comparison conditions are often called Boolean expressions because they evaluate to a simple true or false result Their syntax is summarized in the following diagram and explained in detail after the diagram Syntax 1 405 Condition Comparison Condition Expression p 1 430 Expression p 1 430 T BETWEEN NOT Relational Expression Operator p 1 430 p 1 500 Expression Expression p
181. INTO i FROM tab order by 1 ERT INTO tab2 VALUES i EACH curl FOR SEL j gt 100 THI ONTINUE HQU0 EACH EN LETE FROM FOR ECT c2 c3 INTO i j FROM tab tab WHERE CURRENT OF curl EACH UPDATE tab SET c2 c2 10 WHERE CURRENT OF curl EXECUTE PROCEDURE bar 10 20 INTO i ERT INTO tab2 VALUES i EACH RE foreach_ex A select cursor is closed when any of the following situations occur e No further rows are returned by the cursor e The cursor is a select cursor without a HOLD specification and a transaction completes using COMMIT or ROLLBACK statements e AnEXIT statement executes which transfers control out of the FOREACH statement e An exception occurs that is not trapped inside the body of the FOREACH statement See the ON EXCEPTION statement on page 2 31 e Acursor in the calling procedure that is executing this cursory procedure within a FOREACH loop closes for any reason Using a SELECT INTO Statement The SELECT statement in the FOREACH statement must include the INTO clause It can also include UNION and ORDER BY clauses It cannot use the INTO TEMP clause The syntax of a SELECT statement is shown on page 1 310 2 22 SPL Statements The type and count of each variable in the variable list must match each value returned by the SELECT INTO statement FOREACH Hold Cursors Using the WITH HOLD keyword specifies that the cursor shou
182. Informix Guide to SOL Syntax Informix Guide to SQL Syntax Version 6 0 March 1994 Part No 000 7597 ii THE INFORMIX SOFTWARE AND USER MANUAL ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND EITHER EXPRESSED OR IMPLIED INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE INFORMIX SOFTWARE AND USER MANUAL IS WITH YOU SHOULD THE INFORMIX SOFTWARE AND USER MANUAL PROVE DEFECTIVE YOU AND NOT INFORMIX OR ANY AUTHORIZED REPRESENTATIVE OF INFORMIX ASSUME THE ENTIRE COST OF ALL NECESSARY SERVICING REPAIR OR CORRECTION IN NO EVENT WILL INFORMIX BE LIABLE TO YOU FOR ANY DAMAGES INCLUDING ANY LOST PROFITS LOST SAVINGS OR OTHER INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF OR INABILITY TO USE SUCH INFORMIX SOFTWARE OR USER MANUAL EVEN IF INFORMIX OR AN AUTHORIZED REPRESENTATIVE OF INFORMIX HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES OR FOR ANY CLAIM BY ANY OTHER PARTY IN ADDITION INFORMIX SHALL NOT BE LIABLE FOR ANY CLAIM ARISING OUT OF THE USE OF OR INABILITY TO USE SUCH INFORMIX SOFTWARE OR USER MANUAL BASED UPON STRICT LIABILITY OR INFORMIX S NEGLIGENCE SOME STATES DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES SO THE ABOVE EXCLUSION MAY NOT APPLY TO YOU IN WHOLE OR IN PART THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS AND YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE
183. Informix Guide to SQL Tutorial see the owner naming discussion in Chapter 13 Syntax 1 483 Index Name Index Name Purpose Syntax Usage 1 484 Syntax Use the Index Name segment wherever you see a reference to an index name in a syntax drawing It appears in the following statements ALTER INDEX CREATE INDEX DROP INDEX Identifier gt p 1 469 owner S database Fi owner dbservername database is the name of the database in which the index resides dbservername is the name of the INFORMIX OnLine Dynamic Server database server that is home to database The sign is a literal character that you must use to introduce the database server name owner is the user name of the owner of the index If you are using an ANSI compliant database you must use the owner con vention for indexes that you do not own If you use quotes owner appears exactly as typed The actual name of the index is an SQL identifier If you are creating an index the name must be unique within a database The owner name is case sensitive In an ANSI compliant database if you do not use quotes around the owner name the name of the table owner is stored as uppercase letters For more information see the discussion of case sensitivity in ANSI compliant databases on page 1 508 INTERVAL Field Qualifier INTERVAL Field Qualifier Purpose Use the INTERVAL fi
184. J Groff and P Weinberg Osborne McGraw Hill 1990 Preface vw vi Preface Chapter 1 Table of Contents Introduction Informix Products That Use SQL Intro 3 Products Included in This Manual Intro 3 Other Useful Documentation Intro 4 How to Use This Manual Intro 5 Typographical Conventions Intro 5 Syntax Conventions Intro 5 Example Code Conventions Intro 10 Useful On Line Files Intro 11 ASCII and PostScript Error Message Files Intro 11 The Demonstration Database Intro 12 Creating the Demonstration Database Intro 13 New Features in Informix Version 6 0 Products That Use SQL Intro 14 Syntax SQL Statements 1 5 ANSI Compliance and Extensions 1 7 ALLOCATE DESCRIPTOR 1 9 ALTER INDEX 1 12 ALTER TABLE 1 15 BEGIN WORK 1 35 CHECK TABLE 1 37 CLOSE 1 38 CLOSE DATABASE 1 41 COMMIT WORK 1 43 CONNECT 1 44 CREATE AUDIT 1 55 CREATE DATABASE 1 57 CREATE INDEX 1 62 CREATE PROCEDURE 1 68 viii Table of Contents CREATE PROCEDURE FROM 1 76 CREATE SCHEMA 1 77 CREATE SYNONYM 1 80 CREATE TABLE 1 84 CREATE TRIGGER 1 110 CREATE VIEW 1 136 DATABASE 1 140 DEALLOCATE DESCRIPTOR 1 143 DECLARE 1 145 DELETE 1 159 DESCRIBE 1 162 DISCONNECT 1 167 DROP AUDIT 1 171 DROP DATABASE 1 172 DROP INDEX 1 174 DROP PROCEDURE 1 176 DROP SYNONYM 1 177 DROP TABLE 1 179 DROP TRIGGER 1 181 DROP VIEW 1 183 EXECUTE 1 184 EXECUTE IMMEDIATE 1 190 EXECUTE PROCEDURE 1 192 FETCH 1 194 FLUSH 1 204 FREE 1 207 GET DESCRIPTOR 1 210 GET DIAGNOSTICS
185. L API manual for more information about indicator variables Using the INTO Clause of FETCH When the SELECT statement omits the INTO clause you must specify thedestination of the data whenever a row is fetched The FETCH statement can include an INTO clause to retrieve data into a set of variables This method has the advantage that you can store different rows in different memory locations You cannot use an array of host variables in the INTO clause In the following INFORMIX ESQL C example a series of complete rows is fetched into a program array exec sql begin declare section char wanted_state 2 short int row_count struct customer_t 0 int c_no char fname 15 char lname 15 cust_rec 100 exec sql end declare section main exec sql database stores6 exec sql declare cust cursor for select from customer where state wanted_state printf Enter 2 letter state code Syntax 1 199 FETCH scanf s wanted_state exec sql open cust exec sql fetch cust in cust_rec while SQLCODE 0 printf n s s cust_rec fname cust_rec lname exec sql fetch cust in cust_rec printf n exec sql close cust Fetching a series of rows with ESQL C You can fetch into a program array element only by using an INTO clause in the FETCH statement When you are declaring a cursor do not refer to an array element within the SQL statement Using a System Descriptor
186. LOCATE DESCRIPTOR DECLARE DESCRIBE EXECUTE FETCH OPEN PREPARE PUT and SET DESCRIPTOR statements in this manual for further information about using dynamic SQL statements For further information about the system descriptor area see your SQL API manual GET DIAGNOSTICS GET DIAGNOSTICS Purpose Syntax Usage Use the GET DIAGNOSTICS statement to return diagnostic information about the execution of an SQL statement The GET DIAGNOSTICS statement uses one of two clauses as described in the following list The Statement clause determines a count and overflow information about errors and warnings generated by the most recent SQL statement The EXCEPTION clause provides specific information about errors and warnings generated by the most recent SOL statement fe GET DIAGNOSTICS Sement p 1 222 f EXCEPTION Clause p 1 223 The GET DIAGNOSTICS statement retrieves selected status information from the diagnostics area and retrieves either count and overflow information or information on a specific exception The GET DIAGNOSTICS statement never changes the contents of the diagnostics area Using the SQLSTATE Error Status Code When an SQL statement executes an error status code is automatically generated that represents success failure warning or no data found This error status code is stored in a variable called SQLSTATE Class and Subclass Codes The SQLSTATE status code is a a
187. M orders POW Function The POW function raises the base to the exponent This function requires two numeric arguments The return type is FLOAT The following example returns all the information for circles whose areas 2 7 are less than 1 000 square units SELECT FROM circles WHERE 3 1417 POW radius 2 lt 1000 ROOT Function The ROOT function returns the root value of a numeric expression This function requires at least one numeric argument but no more than two If only one argument is supplied the value 2 is used as a default value The value 0 cannot be used as the base The value returned is FLOAT The first SELECT statement in the following example takes the square root of the expression The second SELECT statement takes the cube root of the expression SELECT ROOT 9 FROM angles square root of 9 SELECT ROOT 64 3 FROM angles cube root of 64 Note The SQRT function uses the form SQRT x ROOT x if no index is given ROUND Function The ROUND function returns the rounded value of an expression The expres sion must be numeric or must be converted to numeric If you omit the digit indication the value is rounded to zero digits or to the ones place The digit limitation of 32 and refers to the entire decimal value Figure 1 17 Expression Positive digit values indicate rounding to the right of the decimal point negative digit values indicate rounding to the left of
188. MEDIATE statement makes it easy to dynamically execute a single simple SQL statement that is constructed during program execution For example you could obtain the name of a database from program input construct the DATABASE statement as a program variable and then use EXECUTE IMMEDIATE to execute the statement which opens the database EXECUTE IMMEDIATE Restricted Statement Types You cannot use the EXECUTE IMMEDIATE statement to execute the following SQL statements CLOSE GET DESCRIPTOR CONNECT OPEN DECLARE PREPARE DISCONNECT SELECT EXECUTE SET CONNECTION EXECUTE PROCEDURE if the procedure returns values FETCH SET DESCRIPTOR GET DIAGNOSTICS WHENEVER Use a PREPARE statement to execute a dynamically constructed SELECT statement The following restrictions apply to the statement contained in the quoted string or in the statement variable name e The statement cannot contain a host language comment e Names of host language variables are not recognized as such in prepared text The only identifiers that you can use are names defined in the database such as table names and columns e The statement cannot reference a host variable list or a descriptor hence it must not contain any question mark placeholders such as those allowed with a PREPARE statement e The text must not include any embedded SQL statement prefix or terminator such as the dollar sign or semicolon or the words EXEC SQL The following exa
189. MP clause FOR UPDATE clause names a list of items to be read from the database specifies the program variables or host variables that receive the selected data names the tables that contain the selected columns sets conditions on the rows that are chosen combines groups of rows into summary results sets conditions on the summary results orders the selected rows creates a temporary table in the current database and puts the results of the query into the table designates the values returned by the select as values that can be updated after a fetch Syntax 1 311 SELECT SELECT Clause The SELECT clause contains the SELECT keyword and the list of database objects or expressions to be selected as shown in the following diagram gt SELECT UNIQUE Select List os List J 4 OE Expression p 1 430 p display S label as N K Table Name p 1 506 View s Name p 1 510 Synonym Name display label is a temporary name that you assign to the expression In the SELECT clause you specify exactly what data is being selected as well as whether you want to omit duplicate values 1 312 Syntax SELECT Allowing Duplicates You can apply the ALL UNIQUE or DISTINCT keywords to indicate whether duplicate values are returned if any exist If you do not specify any keywords all the rows
190. NEVER statement specify WHENEVER SQLERROR CONTINUE and WHENEVER SQLWARNING CONTINUE before the ROLLBACK WORK state ment This prevents the program from looping if the ROLLBACK WORK statement encounters an error or a warning References See the BEGIN WORK and COMMIT WORK statements in this manual In the Informix Guide to SQL Tutorial see the discussion of ROLLBACK WORK in Chapter 5 Syntax 1 307 ROLLFORWARD DATABASE ROLLFORWARD DATABASE Purpose Syntax Usage 1 308 Syntax Use the ROLLFORWARD DATABASE statement with the INFORMIX SE database server to apply the transaction log file to a restored database EEJ ROLLFORWARD DATABASE Dalabase a p 1 421 To restore a database you need both the archive copy of the database and the transaction log that began immediately after the archive copy was made To execute the ROLLFORWARD DATABASE statement you need the DBA privilege Always precede a ROLLFORWARD DATABASE statement with a CLOSE DATABASE statement The ROLLFORWARD DATABASE statement fails if a database is open The ROLLFORWARD DATABASE statement sets an exclusive lock on the database to prevent access by other processes If another process is using the database even if the database is only being read the ROLLFORWARD DATABASE statement fails The database remains locked after the ROLLFORWARD DATABASE statement executes This allows you to check for errors before you give access
191. NG IN usr tmp sal warnings WITH LISTING IN Option The WITH LISTING IN option specifies a filename where compile time warnings are sent After you compile a procedure this file holds one or more warning messages If you do not use the WITH LISTING IN option the compiler does not generate a list of warnings Syntax 1 71 CREATE PROCEDURE The Statement Block Statement Block DEFINE at S 1 72 Syntax tatement p 2 7 ON EXCEPTION Statement p 2 31 CALL Statement p 2 3 Of Kd CONTINUE Statement p 2 6 EXECUTE PROCE Statement p 1 192 DURE EXIT Statement p 2 14 FOR Statement p 2 16 FOREACH Statement p 2 20 IF Statement p 2 24 O A K LET Statement p 2 28 o A RAISE EXCEPTION Statement p 2 36 Kd RETURN Statement p 2 38 SYSTEM Statement p 2 40 K TRACE Statement p 2 42 L A WHILE Statement p 2 46 Ks Subset of SQL ___ Statement p 1 73 BEGIN Statement Block END CREATE PROCEDURE The statement block can be empty which results in a procedure that does nothing You cannot close the current database or select a new database within a procedure You cannot drop the current p
192. NSI compliant database you must use the owner convention for tables that you do not own If you use quotes owner appears exactly as typed Usage The following example shows a table specification empinfo personnel emp_names If you are creating or renaming a table the name of the table must be unique among all the tables synonyms temporary tables and views that already exist in the database VGH If you are creating or renaming a table you must make sure that the combination of owner and name is unique within a database In an ANSI compliant database the table name must include owner unless you are the owner For system catalog tables the owner is informix Syntax 1 507 Table Name Case Sensitivity in ANSI Compliant Databases 1 508 Syntax The database server shifts the owner name to uppercase letters before the statement executes unless the owner name is enclosed in quotes Put quotes around the owner portion of a name if you want the owner to be read exactly as written In the following example the name cathl in the first state ment is upshifted to CATHL before it is used the name nancy in the second statement is not upshifted SELECT FROM cathl customer SELECT FROM nancy customer No problem exists if you create a table with an implicit owner in uppercase letters and the owner s real login name is also in uppercase letters For example suppose that you are the user BROWN and
193. Name 484 INTERVAL Field Qualifier 485 Literal DATETIME 487 Literal Interval 490 Literal Number 493 Procedure Name 495 Quoted String 497 Relational Operator 500 Synonym Name 504 Table Name 506 View Name 510 Syntax 1 3 1 4 Syntax SOL Statements SQL statements are divided into the following categories Data definition statements Data manipulation statements Cursor manipulation statements Dynamic management statements Data access statements Data integrity statements Query optimization information statements Stored procedure statements Auxiliary statements Client Server Connection Statements Optical Statements The specific statements contained in each category are found in the following list Data Definition Statements ALTER INDEX CREATE VIEW ALTER TABLE DATABASE CLOSE DATABASE DROP DATABASE CREATE DATABASE DROP INDEX CREATE INDEX DROP PROCEDURE CREATE PROCEDURE DROP SYNONYM CREATE PROCEDURE FROM DROP TABLE CREATE SCHEMA DROP TRIGGER CREATE SYNONYM DROP VIEW CREATE TABLE RENAME COLUMN CREATE TRIGGER RENAME TABLE Syntax 1 5 SQL Statements Data Manipulation Statements DELETE INSERT LOAD Cursor Manipulation Statements CLOSE DECLARE FETCH Dynamic Management Statements ALLOCATE DESCRIPTOR DEALLOCATE DESCRIPTOR DESCRIBE EXECUTE EXECUTE IMMEDIATE Data Access Statements GRANT LOCK TABLE REVOKE Data Integrity Statements BEGIN WORK CHECK TABLE COMMIT WORK CREATE AUDIT
194. O Often J Sometimes Rarely J Never e On line help Often Sometimes Rarely Never Browse through manuals Often Sometimes Rarely Never 5 How long have you been developing database applications e How many years have you been programming 0 1 3 14 5 L155 e How many years have you been using databases 0 1 3 14 5 L155 e How many years have you been using Informix products 10 11 3 14 5 1 gt 5 6 Have you used other programming languages If so which ones 7 Have you used other database products If so which ones January 1993 8 What other Informix products do you use 9 What is your job title and area of responsibility 10 Is the format of this manual easy to use Consider page size typeface binding diagrams and code examples 11 Additional comments Your Name Company Name Address City State Province Country Zip Postal Code Telephone Number INFORMIX is a registered trademark of Informix Software Inc To mail this card please fold on the dotted line and staple or tape the open end BUSINESS REPLY MAIL FIRSTCLASS PERMIT NO 25 MENLO PARK CA POSTAGE WILL BE PAID BY ADDRESSEE f INFORMIX Informix Software Inc Technical Publications Department 4100 Bohannon Drive Menlo Park California 94025 NO POSTAGE NECESSARY IF MAILED IN THE UNITED STATES
195. ON SET LOCK MODE COMMIT WORK ROLLBACK WORK and UNLOCK TABLE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of locks in Chapter 6 1 262 Syntax OPEN OPEN Purpose Syntax EZ OPEN Use the OPEN statement to activate a cursor associated with a SELECT INSERT or EXECUTE PROCEDURE statement and thereby begin execution of the SELECT INSERT or EXECUTE PROCEDURE statement cursor id cursor variable cursor id cursor variable descriptor descriptor variable sqlda pointer variable name J variable name gt USING SQL DESCRIPTOR descriptor descriptor variable DESCRIPTOR sqlda pointer identifies a cursor that was created by an earlier DECLARE statement is an SQL API variable that identifies a cursor that was created by an earlier DECLARE statement is a quoted string that identifies the system descriptor area that was previously allocated is an SQL API variable name that identifies the system descriptor area that was previously allocated points to an sqlda structure that defines the type and memory location of values that correspond to the question mark placeholder in a prepared statement is a program or host variable whose contents replace a question mark placeholder in a prepared statement Syntax 1 263 OPEN Usage You create a cursor with a statement using the DECLARE statement page 1
196. ORE action list for trigger b d FOR EACH ROW action list for trigger a c FOR EACH ROW action list for trigger b d AFTER action list for trigger a c AFTER action list for trigger b d OY OL ON S The database server treats the triggers as a single trigger and the triggered action is the merged action list All the rules governing a triggered action apply to the merged list as one list and no distinction is made between the two original triggers Guaranteeing Row Order Independence In a FOR EACH ROW triggered action list the result might depend on the order of the rows being processed You can ensure that the result is independent of row order by following these suggestions e Avoid selecting the triggering table in the FOR EACH ROW section If the triggering statement affects multiple rows in the triggering table the result of the SELECT statement in the FOR EACH ROW section varies as Syntax 1 117 CREATE TRIGGER each row is processed This also applies for any cascading triggers See Cascading Triggers on page 1 130 In the FOR EACH ROW section avoid updating a table with values derived from the current row of the triggering table If the triggered actions mod ify any row in the table more than once the final result for that row depends on the order in which rows from the triggering table are processed Avoid modifying a table in the FOR EACH ROW section that is selected by another triggered statem
197. OSE statement and if an error occurs while the last buffered rows are being written to the database the transaction is still committed For the use of insert cursors and the WITH HOLD clause see the DECLARE statement on page 1 145 References 1 40 Syntax See the DECLARE FETCH FLUSH FREE OPEN and PUT statements in this manual In the Informix Guide to SQL Tutorial see the discussion of cursors in Chapter 5 CLOSE DATABASE CLOSE DATABASE Purpose Syntax Usage Use the CLOSE DATABASE statement to close the current database aa CLOSE DATABASE Following the CLOSE DATABASE statement the only legal SQL statements are CREATE DATABASE DATABASE and DROP DATABASE A CONNECT state ment or a DISCONNECT statement can also follow a CLOSE DATABASE state ment but only if an explicit connection existed before you issue the CLOSE DATABASE statement You also can use the START DATABASE and ROLLFORWARD DATABASE statements after CLOSE DATABASE Issue the CLOSE DATABASE statement before you drop the current database If your database has transactions you must issue a COMMIT WORK statement before you use the CLOSE DATABASE statement if you have started a transaction The following example shows how to use the CLOSE DATABASE statement to drop the current database DATABASE stores6 CLOSE DATABASE DROP DATABASE stores6 The CLOSE DATABASE statement cannot appear in a multistatement PRE
198. P TABLE statement environment variables and ONCONFIG parameters OnLine follows this order when storing temporary tables The IN dbspace clause You can specify the dbspace where you want the temporary table stored with the IN dbspace clause of the CREATE TABLE statement e The DBSPACETEMP environment variable If you do not use the IN dbspace clause OnLine checks to see if the DBSPACETEMP environment variable is set The DBSPACETEMP environment variable lists dbspaces where tem porary tables can be stored This list can be standard dbspaces temporary dbspaces or both If the environment variable is set OnLine stores the temporary table in one of the dbspaces specified in that list CREATE TABLE The ONCONFIG parameter DBSPACETEMP You can specify a location for temporary tables with the ONCONFIG parameter DBSPACETEMP If you do not use the IN dbspace clause the DBSPACETEMP environment variable or the ONCONFIG parameter DBSPACETEMP by default temporary tables are created in the same dbspace as your database server You can specify more than one dbspace on the environment variable For example you can specify the following dbspace definitions for the DBSPACETEMP environment variable setenv DBSPACETEMP tempspcl tempspc2 tempspc3 Each temporary table created round robins to a dbspace For example if you created three temporary tables the first one temp1 would go into the dbspace called tempspcl the second one te
199. PARE operation Syntax 1 41 CLOSE DATABASE If you use the CLOSE DATABASE statement within a routine called by a WHENEVER statement specify WHENEVER SQLERROR CONTINUE and WHENEVER SQLWARNING CONTINUE before the ROLLBACK WORK state ment This prevents the program from looping if the ROLLBACK WORK statement encounters an error or a warning When you issue the CLOSE DATABASE statement declared cursors are no longer valid You must redeclare any cursors that you want to use References 1 42 Syntax See the CONNECT CREATE DATABASE DATABASE DISCONNECT and DROP DATABASE statements in this manual COMMIT WORK COMMIT WORK Purpose Use the COMMIT WORK statement to commit all modifications made to the database from the beginning of a transaction Syntax COMMIT WORK Usage Use the COMMIT WORK statement when you are sure you want to keep changes made to the database from the beginning of a transaction Use the COMMIT WORK statement only at the end of a multistatement operation The COMMIT WORK statement releases all row and table locks The COMMIT WORK statement closes all open cursors except those declared with hold References See the BEGIN WORK ROLLBACK WORK and DECLARE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of transactions in Chapter 4 Syntax 1 43 CONNECT CONNECT Purpose Use the CONNECT statement to connect to a database environment
200. PIC S9 9 Using the MORE Keyword Use the MORE keyword to determine if the most recently executed SQL statement performed the following actions Stored all the exceptions it detected in the diagnostics area The GET DIAGNOSTICS statement returns a value of N Detected more exceptions than it stored in the diagnostics area The GET DIAGNOSTICS statement returns a value of Y The value of MORE is always N 1 222 Syntax GET DIAGNOSTICS Using the NUMBER Keyword Use the NUMBER keyword to count the number of exceptions that the most recently executed SQL statement placed into the diagnostics area The NUM BER field can hold a value from 1 to 35 000 depending on how many exceptions are counted Using the ROW_COUNT Keyword Use the ROW_COUNT keyword to count the number of rows the most recently executed statement processed ROW_COUNT counts the following number of rows Inserted into a table Updated in a table Deleted from a table The EXCEPTION Clause pose num can var CLASS_ORIGIN aS var CONNECTION ALIAS gt EXCEPTION MESSAGE_LENGTH A MESSAGE_TEXT A RETURNED_SQLSTATE SERVER_NAME a SUBCLASS_ORIGIN 7 en_var is a host variable that specifies an exception number for a GET DIAGNOSTICS statement except_num is a literal integer value that specifies the exception number for a GET DIAGNOSTICS statement The except_num literal indicates one of the exception values from
201. QL close democursor 58 Syntax 1 229 GET DIAGNOSTICS 1 230 Syntax 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 75 76 77 78 719 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 Ta 14 15 16 17 18 EXEC SQL ifdef TRANS strcpy statement COMMIT WORK stmt EXEC SQL commit work EXEC SOL endif printf nProgram Over n exit 1 End of main routine sql_err EXEC SQL BEGIN DECLARE SECTION int exception_count messlen rowcount i char overflow 2 char class 255 subclass 255 message 255 EXEC SQL END DECLARE SECTION int warning 0 int warning 0 if SQLSTATE 0 0 trap 00 01 02 switch SQLSTATE 1 case 0 success return 0 return 0 case 1 warning return 1 warning 1 break case 2 end of data return 2 return 2 default break printf 7 7 9 nnn sn n if SQLCODE printf SQLCODE d n SQLCODE printf Ss SQLSTATE s n statement SQLSTATE EXEC SQL get diagnostics exception_count NUMBER overflow MORE printf NUMBER d n exception_count printf MORE s n overflow for i 1 i lt exception_count i EXEC SQL get diagnostics exception i SQLSTATE RETURNED_SQLSTATE class CLASS_ORIGIN subclass SUBCLASS_ORIGIN message MESS
202. QLCA If the database is an INFORMIX OnLine Dynamic Server database the fourth element of the sqlcawarn structure contains a W after the DATABASE statement executes See the following chart for the name of the variable that each product uses Product Field Name ESQL C sqlca sqlwarn sqlwarn3 ESQL COBOL SQLWARN3 OF SQLWARN OF SQLCA Only the databases stored in your current directory or in a directory specified in your DBPATH environment variable are recognized If you want to specify a database that does not reside in your current directory or in a directory specified by the DBPATH environment variable you must follow the DATABASE keyword with a program or host variable that evaluates to the full pathname of the database excluding the dbs extension Syntax 1 141 DATABASE EXCLUSIVE Keyword The EXCLUSIVE keyword opens the database in exclusive mode and prevents access by anyone but the current user To allow others access to the database you must execute the CLOSE DATABASE statement and then reopen the database without the EXCLUSIVE keyword The following statement opens the stores6 database on the training database server in exclusive mode DATABASE stores6 training EXCLUSIVE If another user has already opened the database exclusive access is denied an error is returned and no database is opened References 1 142 Syntax See the CLOSE DATABASE and CONNECT statements in this manual In the Info
203. R data type 1 19R CHARACTER data type See CHAR data type Character mapping files 5 5R Character string as DATE values 3 29R as DATETIME values 3 10R 3 29R as INTERVAL values 3 15R processing with NLS 1 15R See also Quoted String segment Character position form of FILE and INSERT statements 5 28R Check constraint adding with ALTER TABLE 1 255 definition of 1 985 4 19T specifying at column level 1 985 specifying at table level 1 98S CHECK keyword use in ALTER TABLE 1 255 use in CREATE TABLE 1 985 CHECK TABLE statement syntax and use 1 375 Checking contents of environment configuration file 5 4R Checking for corrupted tables 1 375 chkenv utility description of 5 4R error message for 5 4R Chunk description of 10 4T mirrored 10 5T Client server environment 1 133S CLOSE DATABASE statement effect on database locks 7 7T prerequisites to close 1 415 syntax 1 415 CLOSE statement Index 5 6 Index closing a select cursor 1 385 closing an insert cursor 1 39S cursors affected by transaction end 1 405 syntax 1 385 with concatenation operator 1 432S CLUSTER keyword syntax in ALTER INDEX 1 12S in CREATE INDEX 1 635 use in ALTER INDEX 1 128 in CREATE INDEX 1 645 Clustered index creating with CREATE INDEX 1 645 description of 10 25T with ALTER INDEX 1 125 with audit trails 1 645 COBOL 5 6T Codd E F 1 11T 8 4T 8 32T Code set for crtcmap text file 5 6R mapping non standard to standard 5 5R mapping with crtcmap util
204. RE UPDATE WHERE In a database that is not ANSI compliant if any statement fails to access any rows the database server returns 0 In a multistatement prepare if any statements fail to access rows in either ANSI databases and databases that are not ANSI compliant the database server returns SOQLNOTFOUND 100 EXECUTE References See the ALLOCATE DESCRIPTOR DEALLOCATE DESCRIPTOR DECLARE EXECUTE IMMEDIATE GET DESCRIPTOR PREPARE PUT and SET DESCRIPTOR statements in this manual In the Informix Guide to SQL Tutorial see the discussion of the EXECUTE statement in Chapter 5 Syntax 1 189 EXECUTE IMMEDIATE EXECUTE IMMEDIATE Purpose Syntax Usage 1 190 Syntax Use the EXECUTE IMMEDIATE statement to perform the functions of the following SQL statements in one step PREPARE EXECUTE and FREE Quoted ASE EXECUTE IMMEDIATE String i p 1 497 statement variable name statement is a program or host variable that contains a character string variable name that consists of one or more SQL statements The quoted string is a character string comprising one or more SQL statements The string or the contents of the statement variable name is parsed and executed if correct then all data structures and memory resources are released immediately In the usual method of dynamic execution these func tions are distributed among the following statements PREPARE EXECUTE and FREE The EXECUTE IM
205. RE PUT SELECT and UPDATE statements in this manual In the Informix Guide to SQL Tutorial see the discussions of cursors and data modification in Chapter 5 and Chapter 6 respectively 1 158 Syntax DELETE DELETE Purpose Syntax DELETE FROM Usage Use the DELETE statement to delete one or more rows from a table ne WHERE Condition p 1 404 cursor curREnT oF Fane cursor name is the name of the cursor that you previously declared and positioned If you use the DELETE statement without a WHERE clause all the rows in the table are deleted If you use the DELETE statement outside a transaction in a database that uses transactions each DELETE statement that you execute is treated as a single transaction Each row affected by a DELETE statement within a transaction is locked for the duration of the transaction therefore a single DELETE statement that affects a large number of rows locks the rows until the entire operation is complete If the number of rows affected is very large you might exceed the limits your operating system places on the maximum number of simulta neous locks If this occurs you can either reduce the scope of the DELETE statement or lock the entire table before you execute the statement Syntax 1 159 DELETE If you specify a view name the view must be updatable See Updating through Views on page 1 139 for an explanation of an updatable view I
206. RETURNING clause can return zero or two values if it is cursory it returns more than one row with zero or two values returned for each row RETURNING INT RETURNING INT INT The receiving procedure or program must be written appropriately to accept the information 1 70 Syntax CREATE PROCEDURE Describing the Procedure in the DOCUMENT Clause The quoted string or strings in the DOCUMENT clause provide a synopsis and description of the procedure The DOCUMENT text is intended for the user of the procedure Anyone with access to the database can query the sysproc body system catalog table to obtain a description of one or all of the procedures stored in the database For example to find the description of the procedure called do_something you execute the following query SELECT data FROM sysprocbody b sysprocedures p WHERE b procid p procid join between the two catalogs AND p procname do_something look for procedure do_something AND b datakey D want user document ORDER BY b seqno in order The rows returned are the complete text as supplied in the DOCUMENT clause of the CREATE PROCEDURE statement CREATE PROCEDURE ret_sal dep_no INT name CHAR 8 default user RETURNING INT END PROCEDURE DOCUMENT Usage salary dept required name default your name returns your or someone else s salary Warning This procedure sends mail on illegal use WITH LISTI
207. ROCEDURE INTO varl FROM tabl SELECT Statements in WHILE and FOR Statements 1 482 Syntax If you use a SELECT statement in a WHILE or FOR loop and if you need to enclose it in parentheses enclose the entire SELECT statement in a BEGIN END block The SELECT statement in the first WHILE statement in the following example is interpreted as a call to the procedure var1 the second WHILE statement is interpreted correctly DEFINI WHILE SI U S END W WHILE END W E varl var2 INT var2 varl ELECT coll INTO var3 FROM TAB error seen as call varl ION ELECT co2 FROM tab2 HILE var2 varl EGIN SELECT coll INTO var3 FROM TAB ok syntax UNION SELECT co2 FROM tab2 D HILE Identifier The SET Keyword in the ON EXCEPTION Statement If you use a statement that begins with the keyword SET inside the statement ON EXCEPTION you must enclose it in a BEGIN END block This includes the following statements SET CONSTRAINTS SET LOCK MODE SET DEBUG FILE SET LOG SET EXPLAIN SET OPTIMIZATION SET ISOLATION The following example shows the ON EXCEPTION statement which returns an error and a correct ON EXCEPTION statement that uses the BEGIN END block ON EXCEPTION IN 107 SET LOCK MODE TO WAIT error value expected not lock END EXCEPTION ON EXCEPTION IN 107 BEGIN SET LOCK MODE TO WAIT ok END END EXCEPTION References In the
208. ROLL keyword creates a scroll cursor which you can use to fetch rows of the active set in any sequence The database server implements a scroll cur sor by creating a temporary table to hold the active set With the active set retained as a table you can fetch the first last or any intermediate rows as well as fetch rows repeatedly without having to close and reopen the cursor These abilities are discussed under the FETCH statement see page 1 194 The database server retains the active set for a scroll cursor until the cursor is closed On a multiuser system the rows in the tables from which the active set rows were derived might change after a copy is made in the temporary table If you use a scroll cursor within a transaction you can prevent copied rows from changing either by setting the isolation level to Repeatable Read Syntax 1 149 DECLARE available only with INFORMIX OnLine Dynamic Server or by locking the entire table in share mode during the transaction See the SET ISOLATION statement on page 1 366 and the LOCK TABLE statement on page 1 260 You cannot associate a scroll cursor with an INSERT statement and you cannot declare a scroll cursor with the FOR UPDATE keywords The following example creates a scroll cursor DECLARE sc_cur SCROLL CURSOR FOR SELECT FROM orders Hold Cursor 1 150 Syntax If you use the WITH HOLD keywords you create a hold cursor A hold cursor remains open after a transaction
209. RT INTO emp_list VALUES last first 800 555 1234 LET x SELECT count FROM emp_list R P gw ETURN x ROCEDURE When an error occurs the database server searches for the last declaration of the ON EXCEPTION statement that traps the particular error code This can be an ON EXCEPTION statement that has the error number in the IN clause or an ON EXCEPTION statement without an IN clause If no pertinent ON EXCEP TION statement is found the error code passes back to the caller procedure application or interactive user and execution aborts ON EXCEPTION The following example uses two ON EXCEPTION statements with the same error number so that error number 691 can be trapped in two levels of nesting CREATE PROCEDURE delete_cust cnum INT ON EXCEPTION I 691 children exist BEGIN Begin end is necessary so that other DELETEs don t get caught in here ON EXCEPTION IN 691 DELETE FROM another_child WHERE num cnum DELETE FROM orders WHERE customer_num cnum END EXCEPTION for 691 DELETE FROM orders WHERE customer_num cnum END DELETE FROM cust_calls WHERE customer_num cnum DELETE FROM customer WHERE customer_num cnum END EXCEPTION DELETE FROM customer WHERE customer_num cnum END PROCEDURE Using the IN Clause to Trap Specific Exceptions A trap is triggered if either the SQL error code or the ISAM error co
210. R_NAME field is blank The Contents of the SERVER_NAME Field The SERVER_NAME field contains different information after you execute the following statements CONNECT the SERVER_NAME field contains the name of the server to which you connect or fail to con nect The SERVER_NAME field is blank if you do not have a current connection or if you make a default connection SET CONNECTION the SERVER_NAME field contains the name of the server to which you switch or fail to switch DISCONNECT the SERVER_NAME field contains the name of the server from which you disconnect or fail to disconnect If you disconnect and then you execute a DISCONNECT statement for a con nection that is not current the SERVER_NAME field remains unchanged DISCONNECT ALL the SERVER_NAME field is blank if the statement executes successfully If the state ment does not execute successfully the SERV ER_NAME field contains the names of all the servers from which you did not disconnect However this does not mean the connection still exists 1 226 Syntax GET DIAGNOSTICS The DATABASE Statement When you execute a DATABASE statement the SERVER_NAME field contains the name of the server on which the database resides Using the CONNECTION_NAME Keyword Use the CONNECTION_NAME to specify a name for the connection used in your CONNECT or DATABASE statements When the CONNECTION_NAME Keyword is Updated GET DIAGNOSTICS updates the CONNECTION_NAME fiel
211. S INTO TEMP clause 1 341S 2 83T IS NULL condition 1 327S join 2 71T to 2 79T joining tables in WHERE clause 1 331S LIKE or MATCHES condition 1 328S multiple table 2 69T natural join 2 75T null values in the ORDER BY clause 1 3395 ORDER BY clause 1 3375 2 13T ORDER BY clause and NLS 1 15R outer join 3 21T to 3 31T privilege for 11 6T 11 8T relational operator condition 1 326S restrictions with INTO clause 1 276S rowid 3 16T 3 21T ROWID keyword 1 435S SELECT clause 1 3125 2 12T to 2 28T select numbers 1 339S selecting a substring 2 27T selecting expressions 2 46T selection list 2 12T self join 3 11T single table 2 11T singleton 1 318S 2 29T subquery 3 32T to 3 42T subquery with WHERE keyword 1 326S syntax 1 310S UNION operator 1 344S 3 43T use of expressions 1 313S using for join 2 8T for projection 2 7T for selection 2 5T WHERE clause and NLS 1 15R with Condition segment 1 404S DECLARE 1 145S FOREACH 2 208 INSERT 1 253S INTO keyword 1 198S LET 2 295 writing rows retrieved to an ASCII file 1 378S Selection described 2 5T Self join assigning column names with INTO TEMP 3 12T description of 1 333S 3 11T See also Join Self referencing query 3 11T 4 22T Self referencing query See also Self join Semantic integrity 4 18T 9 3T Sequential access See Disk access sequential Sequential cursor definition of 1 149S 5 23T use of 1 1495 with FETCH 1 195S SERIAL data type description of 3 19R 9 7T
212. S for INTERVAL 3 13R 1 485S 1 491S Query cyclic 4 22T improving performance of 13 27T to 13 41T performance of 13 3T to 13 42T piping results to another program 1 2725 self referencing 4 22T sending results to an operating system file 1 271S sending results to another program 1 2725 stated in terms of data model 1 7T time costs of 13 14T Query optimization information statements 1 65 Query optimizer See Optimizer Query plan autoindex path 13 29T chosen by optimizer 13 11T description of 13 22T display with SET EXPLAIN 13 12T indexes in 13 26T use in analyzing performance 13 29T Question mark as placeholder in PREPARE 1 2735 naming variables in PUT 1 287S replacing with USING keyword 1 268S wildcard in Condition segment 1 411S Quoted string in expression 1 436S syntax in Condition segment 1 405S in expression 1 462S in INSERT 1 250S use in expression 1 438S in INSERT 1 498S with LIKE MATCHES keywords 1 328S See also Quoted String segment Quoted String segment DATETIME INTERVAL values as strings 1 498S syntax 1 497S wildcards 1 498S with LIKE in a condition 1 498S Quotes single and double Intro 6S R RAISE EXCEPTION statement exiting a loop 14 23T syntax 2 365 REAL data type See SMALLFLOAT data type RECOVER TABLE statement archiving a database with audit trails 1 292S manipulating audit trail file 1 293S syntax 1 2925 Recursion in a stored procedure 14 24T Recursive relationship 8 11T 8
213. SER CHA CHA CHA CHA address2 CHA CHA CHA CHA CHA IAL city state zipcode phone CREATE INDEX cathtmp ON customer customer_num DESC CREATE INDEX c_temp2 ON customer customer_num zipcode CREATE INDEX References See the ALTER INDEX DROP INDEX and CREATE TABLE statements in this manual In the Informix Guide to SQL Tutorial see the discussions of indexes in Chapter 3 Chapter 10 and Chapter 13 Syntax 1 67 CREATE PROCEDURE CREATE PROCEDURE Purpose Syntax EEJ CREATE PROCEDURE Name p 1 495 3 ow Parameter Use the CREATE PROCEDURE statement to name and define a stored procedure Procedure RETURNING Clause p 1 70 p 1 69 END Usage 1 68 Syntax PROCEDURE WITH f DOCUMENT Suore ee LISTING IN pathname pathname is the full pathname of the file that is to contain the warnings of the procedure The file must be on the host machine of the database server that serves the database The entire length of a CREATE PROCEDURE statement must be less than 64 kilobytes This length is the literal length of the CREATE PROCEDURE state ment including blank space and tabs You can use a CREATE PROCEDURE statement only within a PREPARE statement If you want to create a procedure for which the text is known at compile time you must use a CREATE PROCEDURE FROM statement If t
214. STICS statement to interpret the SQLSTATE value The following example illustrates a simple OPEN statement in INFORMIX ESQL C exec sql declare s_curs cursor for execute procedure new_proc exec sql open s_curs Opening an Insert Cursor 1 266 Syntax When you open an insert cursor the cursor passes the INSERT statement to the database server which checks the validity of the keywords and column names The database server also allocates memory for an insert buffer to hold new data See the DECLARE statement on page 1 145 An OPEN statement for a cursor associated with an INSERT statement cannot include a USING clause The following INFORMIX ESQL C example illustrates an OPEN statement with an insert cursor exec sql prepare sl from insert into manufact values npr napier exec sql declare in_curs cursor for sl exec sql open in_curs exec sql put in_curs exec sql close in_curs OPEN Reopening a Select Cursor The values named in the USING clause are evaluated only when the cursor is opened While the cursor is open subsequent changes to program variables in the USING clause do not change the active set of selected rows The active set remains constant until a subsequent OPEN statement closes the cursor and reopens it or until the program closes the open cursor which releases the active set Reopening the cursor creates a new active set based on the current values of the variables If the
215. String Purpose The Quoted String segment is used in the following statements and segments INSERT statement SELECT statement e Condition segment e Expression segment in constant expressions Syntax gt a character tt C character woe character is an ASCII character Usage The string constant must be written on a single line that is you cannot use embedded new lines Using Quotes in Strings The single quote has no special significance in string constants delimited by double quotes Likewise the double quote has no special significance in strings delimited by single quotes For example the following strings are valid Nancy s puppy jumped the fence Billy told his kitten no Syntax 1 497 Quoted String If your string is delimited by double quotes you can include a double quote in the string by preceding the double quote with another double quote as shown in the following string Enter y to select this row DATETIME and INTERVAL Values as Strings You can enter DATETIME and INTERVAL data in the literal forms described in the Literal DATETIME and Literal Interval segments beginning on pages 1 487 and 1 490 respectively or you can enter them as quoted strings Valid literals that are entered as character strings are converted automatically into DATETIME or INTERVAL values The following INSERT statements use quoted strings to enter INTERVAL and DATETIM
216. T FROM orders WHERE ship_date TODAY CURRENT Function 1 440 Syntax The CURRENT function returns a DATETIME value with the date and time of day showing the current instant If you do not specify a datetime qualifier the default qualifiers are YEAR TO FRACTION 3 You can use the CURRENT function in any context in which you can use a literal DATETIME page 1 487 If you specify CURRENT as the default value for a column it must be a DATETIME column and the qualifier of CURRENT must match the column qualifier An example of this follows CREATE TABLE new_acct coll int col2 DATETIME YEAR TO DAY EFAULT CURRENT YEAR TO DAY iw If you use the CURRENT keyword in more than one place in a single statement identical values can be returned at each point of the call You can not rely on the CURRENT function to provide distinct values each time it executes The returned value comes from the system clock and is fixed when any SQL statement starts For example any calls to CURRENT from an EXECUTE PRO CEDURE statement returns the value when the stored procedure starts The CURRENT function is always evaluated in the database server where the current database is located If the current database is in a remote database server the returned value is from the remote host The CURRENT function might not execute in the physical order in which it appears in a statement You should not use the CURRENT function to mark t
217. T restrictions with LIKE or MATCHES 2 37T restrictions with relational expression 2 29T selecting a BYTE column 3 5R syntax 1 425S with stored procedures 2 95 2 135 BYTE value displaying 2 11T C C shell how to set environment variables 4 5R cshre file 4 4R login file 4 4R Calculated expression restrictions with GROUP BY 1 334S See also Expression segment CALL keyword in the WHENEVER statement 1 398S 1 401S CALL statement assigning values with 14 21T executing a procedure 14 9T syntax 2 3S call_type table in stores6 database columns in A 5R Candidate key defined 8 23T Cardinality 8 9T Cardinality in relationship 8 13T Caret wildcard in Condition segment 1 411S Cartesian product basis of any join 2 71T description of 2 69T Cascading deletes defined 1 225 1 975 4 21T locking associated with 1 245 1 985 4 21T logging 1 245 1 985 4 21T restriction 1 24S 1 98S 4 22T syntax 1 215 1 945 Cascading triggers and triggering table 1 127S 1 131S description of 1 130S maximum number of 1 130S scope of correlation names 1 125S triggered actions 1 118S Catalog See System catalog Chaining synonyms 12 18T CHAR data type 9 15T changing data types 3 23R description of 3 6R in INSERT 1 4985 in relational expressions 2 29T replacing with TEXT 10 27T replacing with VARCHAR 10 26T subscripting 2 44T substrings of 2 27T syntax 1 425S truncation signalled 5 12T using as default value 1 195 1 89S versus NCHA
218. TICS Purpose Use the UPDATE STATISTICS statement to update system catalog tables with information used to determine optimal query plans In addition you can use the UPDATE STATISTICS statement to force stored procedures to be reoptimized 1 392 Syntax UPDATE STATISTICS Syntax UPDATE STATISTICS FOR PROCEDURE Procedure Name p 1 495 DROP EOW am DISTRIBUTIONS able FOR TABLE ene p 1 506 Synonym TR p 1 504 N MEDIUM A ae RESOLUTION percent A FOR Name ae TABLE p 1 506 conf J Synonym TA p 1 504 HIGH A mae RESOLUTION percent a FOR Name TABLE p 1 506 Name p 1 504 column the name of a column in the specified table You cannot create distributions for BYTE or TEXT columns the expected fraction of times that sampling should produce the same results as using HIGH mode The range of accept able values for conf is limited to 0 80 0 99 The default value is 0 95 Syntax 1 393 UPDATE STATISTICS percent the desired resolution in units of percent so that 0 1 means the data is divided into bins each containing on average 0 1percent of the data The minimum resolution possible for a table is 1 nrows where nrows is the number of rows in the table The default value is 2 5 percent for MEDIUM distributions and 0 5 percent for HIGH distributions Usage When you issue an UPDAT
219. TRIGGER For an INFORMIX OnLine Dynamic Server database without logging OnLine does not defer constraint checking on the triggering statement In this case it immediately returns an error if the triggering statement violates a constraint OnLine does not allow the SET CONSTRAINTS statement in a triggered action OnLine checks this restriction when you activate a trigger because the statement could occur inside a stored procedure For an INFORMIX SE database with or without logging constraint checking occurs prior to the triggered action If a constraint violation results from the triggering statement INFORMIX SE returns an error immediately Preventing Triggers from Overriding Each Other 1 132 Syntax When you activate multiple triggers with an UPDATE statement it is possible for a trigger to override the changes made by an earlier trigger If you do not want the triggered actions to interact you can split the UPDATE statement into multiple UPDATE statements each of which updates an individual col umn As another alternative you can create a single update trigger for all col umns that require a triggered action Then inside the triggered action you can test for the column being updated and apply the actions in the desired order This approach however is different than having the database server apply the actions of individual triggers and it has the following disadvan tages e Ifthe trigger has a BEFORE action it applies
220. UTE PROCE DURE statement or the characteristics of each column in the INSERT state ment are returned in the system descriptor area Each value in the system descriptor area describes one returned column or expression Each field and its possible contents are described in your SQL API manuals The following INFORMIX ESQL C example shows how a GET DESCRIPTOR statement can be used to obtain data type information from the demodesc system descriptor area exec sql get descriptor demodesc value index type TYPE len LENGTH name NAME printf Column d type d len d name s n index type len name The value returned by the database server into the TYPE field is a defined integer You can evaluate the type returned by testing for a specific integer value The codes for the TYPE field are listed in the embedded language product manuals In X Open mode the X Open code is returned to the TYPE field You must not to mix the two modes because errors can result For example if a partic ular type is not defined under X Open mode but is defined for Informix products the execution of a GET DESCRIPTOR statement can result in an error In X Open mode a warning message appears if ILENGTH IDATA or ITYPE is used It indicates that these types are not standard X Open fields for a system descriptor area Syntax 1 213 GET DESCRIPTOR 1 214 Syntax If the TYPE of a fetched value is DECIMAL or MONEY the data
221. X ESQL C struct sqlda sdp exec sql open selcurs using descriptor sdp The Relationship Between OPEN and FREE The database server allocates resources to prepared statements and open cursors If you release resources with a FREE cursor id or FREE cursor variable statement you cannot use the cursor unless you declare the cursor again If you execute a FREE statement id or FREE statement id variable statement you cannot open the cursor associated with the statement id or statement id variable unless you prepare the statement id or statement id variable again Syntax 1 269 OPEN References 1 270 Syntax See the CLOSE DECLARE and FREE statements in this manual because they are cursor related See the PUT and FLUSH statments also in this manual for insert cursors See the ALLOCATE DESCRIPTOR DEALLOCATE DESCRIPTOR DESCRIBE EXECUTE FETCH GET DESCRIPTOR PREPARE PUT and SET DESCRIPTOR statements in this manual for further information about dynamic SQL statements In the Informix Guide to SQL Tutorial see the discussion of the OPEN statement in Chapter 5 Refer also to your SQL API manual for further information about the system descriptor area and the sqlda structure OUTPUT OUTPUT Purpose Syntax Usage Use the OUTPUT statement to send query results directly to an operating system file or to pipe it to another program SELECT EZE oureurto filename Statement H N p 1 3
222. X statement to put the data in a table in the order of an existing index or to release an index from the clustering attribute Mm ALTER INDEX dex Nae TO T T CLUSTER NOT The ALTER INDEX statement works only on indexes that are created with the CREATE INDEX statement it does not affect constraints created with the CREATE TABLE statement You cannot use a ROLLBACK WORK statement to undo an ALTER INDEX statement When you roll back a transaction that contains an ALTER INDEX statement the index remains altered you do not receive an error message When you have an audit trail on the table you cannot use the ALTER INDEX statement When you want to change an index on an audited table you must first drop the audit on the table alter the index and create anew audit for the table You cannot alter the index of a temporary table The TO CLUSTER Option 1 12 Syntax The TO CLUSTER option causes the rows in the physical table to reorder to the indexed order ALTER INDEX The following example shows how the ALTER INDEX TO CLUSTER statement is used to physically order the rows in the orders table The CREATE INDEX statement creates an index on the customer_num column of the table then the ALTER INDEX statement causes the physical ordering of the rows CREATE INDEX ix_cust ON orders customer_num ALTER INDEX ix_cust TO CLUSTER Reordering causes rewriting the entire file This process can take
223. XCONRETRY 4 34R NFORMIXCONTIME 4 34R NFORMIXDIR 4 36R 12 14T NFORMIXSERVER 4 36R 12 14T NFORMIXSHMBASE 4 37R NFORMIXSTACKSIZE 4 38R INFORMIXTERM 4 38R LANG 4 49R LANG and crtcmap utility 5 5R LC_COLLATE 4 50R LC_CTYPE 4 51R LC_MONETARY 4 52R LC_NUMERIC 4 53R LC_TIME 4 53R listed 4 8R listed by topic 4 9R listed for NLS 4 9R listed for UNIX 4 9R NLS environment variables listing 4 9R ONCOMFIG 4 39R overriding a setting 4 4R 4 30R PATH 4 54R 12 14T PSORT_DBTEMP 4 40R PSORT_NPROCS 4 41R rules of precedence 4 7R setting at the command line 4 4R setting in a shell file 4 4R SQLEXEC 4 41R SQLRM 4 41R 4 42R SQLRMDIR 4 43R TERM 4 55R TERMCAP 4 56R 12 14T TERMINFO 4 56R UNIX environment variables listing 4 9R where to set 4 4R Te cee cee aas cee cee A ee ee ee B an Index 17 18 Index Equals relational operator 2 30T 2 71T Equi join 2 71T ERROR 1 400S Error checking continuing after error in stored procedure 2 345 error status with ON EXCEPTION 2 328 exception handling 14 27T in stored procedures 14 27T simulating errors 14 31T with SYSTEM 2 40S ERROR keyword in the WHENEVER statement 1 398S Error messages for NLS 1 21R for trigger failure 15 14T generating in a trigger 15 14T retrieving trigger text in a program 15 16T 15 17T Errors after DELETE 6 4T at compile time 14 6T codes for 5 11T dealing with 5 16T detected on opening cursor 5 20T during
224. Y FROM manufact The second statement in the preceding example adds five days to each value of lead_time selected from the manufact table Syntax 1 441 Expression UNITS Keyword 1 442 Syntax The UNITS keyword enables you to display a simple interval or increase or decrease a specific interval or datetime value If n is not an integer it is rounded down to the nearest whole number when it is used In the following example the first SELECT statement uses the UNITS keyword to select all the manufacturer lead times increased by five days The second SELECT statement finds all the calls that were placed more than 30 days ago If the expression in the WHERE clause returns a value greater than 99 maxi mum number of days the query fails The last statement increases the lead time for the ANZA manufacturer by two days SELECT lead_time 5 UNITS DAY FROM manufact SELECT FROM cust_calls WHERE TODAY call_dtime gt 30 UNITS DAY UPDATE manufact SET lead_time 2 UNITS DAY lead_time WHERE manu_code ANZ Function Expressions Expression A function expression takes an argument as shown in the following diagram Algebraic gt 3 Functions 7 p p 1 444 DBINFO NJ Function _ p 1 448 Exponential and N Logarithmic Functions p 1 451 HEX n Function A p 1 452 LENGTH KN Function A p 1 453 Time No
225. Y clause all rows in the table make up a single group The following example returns the average price of all the values in the table as long as more than ten rows are in the table SELECT AVG total_price FROM items HAVING COUNT gt 10 ORDER BY Clause Use the ORDER BY clause to sort query results by the values contained in one or more columns ORDER BY Clause column name Table Name p BSO p 1 506 DESC View N Name L A p 1 510 ORDER BY Synonym N Name Z p 1 504 S alias N select A number KN display A label Ma rowid ay column name isthe name of a column from the SELECT clause in which you want to sort the query results display label is the display label used for a column or expression in the select list select number is an integer that represents the placement of a column or expression in the SELECT clause Syntax 1 337 SELECT alias is aname you attach to a table or view within the scope of the SELECT statement rowid is a virtual column that you can use on a SELECT statement You can do an ORDER BY on a column or on an aggregate expression when you use SELECT or a display label in your SELECT statement The following query explicitly selects the order date and shipping date from the orders table and then rearranges the query by the order date By default the query results are listed in ascending orde
226. YTE data type If TYPE contains an 11 or a 12 you must use the SET DESCRIPTOR statement to reset TYPE to 116 which indicates FILE type References See the ALLOCATE DESCRIPTOR DEALLOCATE DESCRIPTOR DECLARE DESCRIBE EXECUTE FETCH GET DESCRIPTOR OPEN PREPARE and PUT statements in this manual for further information about using dynamic SQL statements For further information about the system descriptor area see your SQL API product manual Syntax 1 359 SET EXPLAIN SET EXPLAIN Purpose Syntax Usage 1 360 Syntax Use the SET EXPLAIN statement to obtain a measure of the work involved in performing a query BEJE SET EXPLAIN a ON 7 OFF The SET EXPLAIN statement executes during the database server optimization phase which occurs when you initiate a query For queries associated with a cursor if the query is prepared and does not have host vari ables optimization occurs when you prepare it otherwise it occurs when you open the cursor When you issue a SET EXPLAIN ON statement the path chosen by the optimizer for each subsequent query is written to a file with the name sqexplain out The SET EXPLAIN ON statement remains in effect until you issue a SET EXPLAIN OFF statement or until the program ends Table names in the sqexplain out file are qualified by the owner name for example owner customer If the file already exists subsequent output is appended to the file If the client application and the
227. a long time and it requires sufficient disk space to maintain two copies of the table While a table is clustering the table is locked IN EXCLUSIVE MODE When another process is using the table to which index name belongs the database server cannot execute the ALTER INDEX statement with the TO CLUSTER option it returns an error unless lock mode is set to WAIT When lock mode is set to WAIT the database server retries the ALTER INDEX statement Over time if you modify the table you can expect the benefit of an earlier cluster to disappear because rows are added in a space available order not sequentially You can recluster the table to regain performance by issuing another ALTER INDEX TO CLUSTER statement on the clustered index You do not need to drop a clustered index before issuing another ALTER INDEX TO CLUSTER statement on a currently clustered index The TO NOT CLUSTER Option The NOT option drops the cluster attribute on the index name without affecting the physical table Because there can be only one clustered index per table you must use the NOT option to release the cluster attribute from one index before you assign it to another For example the following series of statements illustrates how clustering is removed from one index and the table is physically reclustered by a second index CREATE UNIQUE INDEX ix_ord ON orders order_num CREATE CLUSTER INDEX ix_cust ON orders customer_num ALTER INDEX ix_c
228. a type e Expression in a constant expression p YEAR pa MONTH ka TO YEAR p N pay N TO MONTH pi N HOUR Re TO DAY A N MINUTE Te TO HOUR A N SECOND eS TO MINUTE A N A a TO SECOND A pa TO FRACTION tes digit digit is a single integer between 1 and 5 that indicates how many digits of precision the fraction is measured Specify the largest unit for the first DATETIME value after the word TO spec ify the smallest unit for the value The keywords imply that the following values are used in the DATETIME object YEAR specifies a year numbered from A D 1 to 9999 MONTH specifies a month numbered from 1 to 12 DAY specifies a day numbered from 1 to 31 as appropriate to the month in question DATETIME Field Qualifier HOUR specifies an hour numbered from 0 midnight to 23 MINUTE specifies a minute numbered from 0 to 59 SECOND specifies a second numbered from 0 to 59 FRACTION specifies a fraction of a second with up to five decimal places The default scale is three digits thousandth of a second The following examples show DATETIME qualifiers DAY TO MINUTE YEAR TO MINUTE DAY TO FRACTION 4 MONTH TO MONTH Syntax 1 429 Expression Expression 1 430 Syntax An expression is one or more pieces of data contained in or derived from the database or database server The Expression segment is used in the following statements and seg
229. acc_num INTEGER PRIMARY KEY CONSTRAINT num acc_code INTEGER UNIQUE CONSTRAINT code acc_descr CHAR 30 Using Blob Data Types in Constraints You cannot place a unique primary key or referential constraint on BYTE or TEXT columns However youcan check for null or non null values by placing a check constraint on a BYTE or TEXT column Syntax 1 91 CREATE TABLE The Constraint Definition Option Constraint Definition C sa wal column_Z gt DISTINCT Constraint CONSTRAINT Name PRIMARY p 1 419 KEY 3 REFERENCES N FOREIGN KEY oe 2 Cue p 1 94 CHECK Clause A p 1 98 column is the name of the column The constraint definition option allows you to create constraints for a single column or a set of columns You can include up to 16 columns in a list of columns The total length of all the columns cannot exceed 255 bytes You can use up to eight columns inclusive in an INFORMIX SE list of columns The total length of all the columns cannot exceed 120 bytes Defining a Column as Unique You can use the UNIQUE keyword to require that a single column or set of columns accepts only unique data You cannot insert duplicate values in a column that has a unique constraint Each column named in a unique constraint must be a column in the table and cannot appear in the constraint list more than once The following example creates a simple table that
230. ain SYSTEM statements the operating system command runs with the permissions of the user executing the procedure 2 40 SPL Statements SYSTEM The following example shows the use of a SYSTEM statement CREATE PROCEDURE sensitive_update END LET mailcall mail headhoncho lt alert code that evaluates if operator tries to execute a certain command then send email to system administrator SYSTEM mailcall PROCEDURE sensitive_update You can use a double pipe symbol to concatenate expressions with a SYS TEM statement as shown in the following example CREATE PROCEDURE sensitive_update2 END code that evaluates if operator tries to execute a certain command then send email to system administrator SYSTEM mail s violation userl user2 lt violation_file PROCEDURE SPL Statements 2 41 TRACE TRACE Purpose Use the TRACE statement to control the generation of debugging output Syntax TRACE ON OFF PROCEDURE Expression p 1 430 Usage Using the TRACE statement generates output that is sent to the file specified by the SET DEBUG FILE TO statement Tracing prints out the current values of all the following items e Variables Procedure arguments Return values SQL error codes ISAM error codes The output of each executed TRACE statement is on a separate line If you use the TRACE statement without first sp
231. ain of the number and type of values being selected In this case you must use an sqlda pointer structure as described in the following list Use the DESCRIBE statement to fill in the sqlda e Allocate memory to hold the data values Name the sqlda in the FETCH statement The following example shows a sample FETCH USING DESCRIPTOR statement in INFORMIX ESQL C exec sql fetch selcurs using descriptor pointer2 Fetching a Row for Update The FETCH statement does not ordinarily lock a row that is fetched Thus the fetched row can be modified updated or deleted by another process imme diately after your program receives it A fetched row is locked in the following cases When you set the isolation level to Repeatable Read each row you fetch is locked with a read lock to keep it from changing until the cursor closes Syntax 1 201 FETCH or the current transaction ends Other programs also can read the locked rows e When you set the isolation level to Cursor Stability the current row is locked e Inan ANSI compliant database an isolation level of Repeatable Read is the default you can set it to something else When you are fetching through an update cursor one declared FOR UPDATE each row you fetch is locked with a promotable lock Other programs can read the locked row but no other program can place a pro motable or write lock therefore the row is unchanged if another user tries to modify it using
232. al effort is made to search the definition of the triggering table for the nonqualified column name For example assume that the following DELETE statement is a triggered action inside the FOR EACH ROW section of a trigger DELETE FROM tabl WHERE col_c col_c2 For the statement to be valid both col_c and col_c2 must be columns from tab1 If col_c2 is intended to be a correlation reference to a column in the trig gering table it must be qualified by either the old or the new correlation name If col_c2 is not a column in tab1 and is not qualified by either the old or new correlation name you get an error When a column is not qualified by a correlation name and the statement is valid independent of the triggered action the column name refers to the cur rent value in the database In the triggered action for trigger t1 in the following example mgr in the WHERE clause of the correlated subquery is an Syntax 1 125 CREATE TRIGGER unqualified column from the triggering table In this case mgr refers to the current column value in empsal because the INSERT statement is valid independent of the triggered action CREATE DATABASE dbl CREATE TABLE empsal empno INT salary INT mgr INT CREATE TABLE mgr eno INT bonus INT CREATE TABLE biggap empno INT salary INT mgr INT CREATE TRIGGER t1 UPDATE OF salary ON empsal AFTER INSERT INTO biggap SELECT FROM empsal WHERE salary lt S
233. also Table Name segment TABLE keyword syntax in UPDATE STATISTICS 1 393S Table Name segment 1 506S Table size calculating 10 12T 10 19T cost of access 13 19T 13 34T with fixed length rows 10 13T with variable length rows 10 14T Table level privilege column specific privileges 1 303S 11 10T default with GRANT 1 237S definition and use 1 236S 11 7T granting 1 235S passing grant ability 1 237S revoking 1 301S See also ALTER TABLE statement TABLES keyword in INFO statement 1 2425 tabtype 2 29R 2 30R 1 60S TAN function syntax in expression 1 4585 use in expression 1 460S tblspace description of 10 7T used for BLOB data 10 18T TEMP keyword syntax in SELECT 1 310S use in SELECT 1 3415 TEMP TABLE keywords syntax in CREATE TABLE 1 845 Temporary files specifying directory with DBTEMP 4 27R tables specifying dbspace with DBSPACETEMP 4 26R Temporary table and active set of cursor 5 24T assigning column names 3 12T building distributions 1 397S creating constraints for 1 102S DBSPACETEMP environment variable 1 100S example 4 11T explicit 1 100S implicit 1 100S location of 1 100S naming 1 100S shared disk space for 10 6T updating statistics 1 394S using to speed query 13 36T when deleted 1 100S TERM environment variable 4 55R TERMCAP environment variable 4 56R 12 14T termcap file and TERMCAP environment variable 4 56R selecting with INFORMIXTERM 4 39R Terminal handling and TERM environment variable
234. ame of the procedure must be unique within a database PNG if you are creating the procedure the combination owner name must be unique within a database The owner name is case sensitive In an ANSI compliant database if you do not use quotes around the owner name the name of the table owner is stored as uppercase letters For more information see the discussion of case sensitivity in ANSI compliant databases on page 1 508 Procedures and SQL Functions with the Same Names If you create a procedure with the same name as an SQL function and then explicitly define that name as a procedure any calls by that name are to the procedure instead of the SQL function That is you cannot use the system function within the statement block in which the procedure is defined The following example uses two length functions The first time the procedure calls the length function it is the SOL function named LENGTH The second time the procedure calls the length function is within a BEGIN END block in which length has been defined as a procedure The second call to length actually uses the user created procedure called length CREATE PROCEDURE test_len RETURNING INT INT DEFINE c INT DEFINE d INT LET c SELECT length fname FROM customer WHERE customer_num 101 BEGIN DEFINE length PROCEDURE LET d length 5 END RETURN c d END PROCEDURE 1 496 Syntax Quoted String Quoted
235. an declare multiple cursors using a single statement identifier For example the following INFORMIX ESQL C example does not return an error exec sql prepare pid from select from customer exec sql declare x cursor for pid exec sql declare y scroll cursor for pid exec sql declare z cursor with hold for pid If you include the ansi compilation flag or DBANSIWARN is set warnings are generated for statements that use dynamic cursor names or dynamic statement id names Some error checking is done at run time The typical checks are found in the following list e Illegal use of cursors that is normal cursors used as scroll cursors Use of undeclared cursors e Bad cursor or statement names empty Checks for multiple declarations of a cursor of the same name are performed at compile time only if the cursor or statement is an identifier For example the first example shows code that follows results in a compile error whereas the code in the second example does not exec sql declare x cursor for select from customer exec sql declare x cursor for select from customer error Results in error exec sql declare x cursor for select from customer strcepy s x exec sql declare s cursor for select from customer Runs successfully Syntax 1 147 DECLARE Overview of Cursor Types Functionally a cursor can be associated with a SELECT statement a select cursor an EXECUTE PROCEDURE
236. an use the INSERT statement to create either a single new row of column values or a group of new rows using data selected from other tables Syntax 1 245 INSERT To insert data into a table you must either own the table or have the Insert privilege for the table see the GRANT statement on page 1 231 To insert data into a view you must have the required Insert privilege and the view must meet the requirements explained in Inserting Rows Through a View If you insert data into a table that has data integrity constraints associated with it the data inserted must meet the constraint criteria If it does not the database server returns an error If you are using effective checking and the checking mode is set to IMMEDIATE all specified constraints are checked at the end of each INSERT statement If the checking mode is set to DEFERRED all specified constraints are not checked until the transaction is committed Specifying Columns If you do not explicitly specify one or more columns data is inserted into columns using the column order of the table established when the table was created or last altered The column order is listed in the syscolumns system catalog table You can use the DESCRIBE statement with an INSERT statement to determine the column order and the data type of the columns in a table For more information about the DESCRIBE statement see page 1 162 The number of columns specified in the INSERT INTO clau
237. annot update SERIAL data type columns The SET clause identifies the columns to be updated and assigns values to each column The clause either pairs a single column to a single expression or lists multiple columns and sets them equal to corresponding expressions Subset of Expressions Allowed in the SET Clause You cannot use an expression made up of aggregate functions in the SET clause For a complete description of syntax and usage see the Expression segment on page 1 430 Subset of SELECT Statements Allowed in the SET Clause 1 386 Syntax A SELECT statement used in a SET clause can return more than one column of information in a row However the SELECT statement cannot return more than one row of information in a table For a complete description of syntax and usage refer to the SELECT statement on page 1 310 UPDATE Single Columns to Single Expressions You can include any number of single column to single expressions in an UPDATE statement The following examples illustrate the single column to single expression form of the SET clause UPDATE customer SET addressl 1111 Alder Court city Palo Alto zipcode 94301 WHERE customer_num 103 UPDATE orders SET ship_charge SELECT SUM total_price 07 FROM items WHERE orders order_num items order_num WHERE orders order_num 1001 UPDATE stock SET unit_price unit_price 1 07 Updating a Column to NULL You can use t
238. anu_code s manu_code and s manu_code m manu_code Estimated Cost 52 Estimated of Rows Returned 130 1 rdtest m SEQUENTIAL SCAN SORT SCAN rdtest m manu_code 2 rdtest s SEQUENTIAL SCAN SORT SCAN rdtest s manu_code MERGE JOIN Merge Filters rdtest m manu_code rdtest s manu_code 3 rdtest i INDEX PATH 1 Index Keys stock_num manu_code Lower Index Filter rdtest i stock_num rdtest s stock_num AND rdtest i manu_code rdtest s manu_code select stock description from stock stock2 where stock description stock2 description and stock unit_price lt stock2 unit_price Estimated Cost 15 Estimated of Rows Returned 370 1 rdtest stock SEQUENTIAL SCAN SORT SCAN rdtest stock description 2 rdtest stock2 SEQUENTIAL SCAN SORT SCAN rdtest stock2 description MERGE JOIN Merge Filters rdtest stock2 description rdtest stock description Other Join Filters rdtest stock unit_price lt rdtest stock2 unit_price Syntax 1 363 SET EXPLAIN 1 364 Syntax The following example shows the SET EXPLAIN output for a simple query and a complex query from the customer table SELECT fname lname company FROM customer Estimated Cost 3 Estimated of Rows Returned 28 1 joe customer SEQUENTIAL SCAN SELECT fname lname company FROM customer WHERE company MATCHES Sport AND customer_num BETWEEN 110 AND 115 ORDER BY lname Estimated Cost 4 Estimated of Rows Returned 1 Temporary Files Requ
239. anu_code FROM stock WHERE NOT EXISTS SELECT stock_num manu_code FROM items WHERE stock stock_num items stock_num AND stock manu_code items manu_code The preceding example works equally well if you use a SELECT in the subquery in place of the column names because the existence of the whole row is tested specific column values are not tested ALL ANY SOME Subquery ANY ALL SOME Subquery Expression Relational Condition ag 430 Operator with gt p 1 500 Subquery ALL p 1 413 ANY SOME ALL is a keyword that denotes that the search condition is true if the comparison is true for every value returned by the sub query If the subquery returns no value the condition is true ANY is a keyword that denotes that the search condition is true if the comparison is true for at least one of the values returned If the subquery returns no value the search condition is false SOME is an alias for ANY Syntax 1 415 Condition 1 416 Syntax In the following example of the ALL subquery the first condition tests whether each total_price is greater than the total price of every item in order number 1023 The second condition produces the same results using the MAX aggregate function total_price gt ALL SELECT total_price FROM items WHERE order_num 1023 total_price gt SELECT MAX total_price FROM items WHERE order_num 1023 The following con
240. any of the identified system descriptor fields the contents of all identified fields are set to zero or null depending on the variable type COUNT Option Use the COUNT option to set the number of items that are to be used in the system descriptor area If you allocate a system descriptor area with more items than you are using you need to set the COUNT field to the number of items that you actually are using The sequence of statements using INFORMIX ESQL C shown in the following example can be used in a program exec sql begin declare section int count itemno type length char chval 21 exec sql end declare section exec sql allocate descriptor desc_100 allocates for 100 items count 2 exec sql set descriptor desc_100 count count VALUE Option Use the VALUE option to assign values from host variables into fields for a particular item in a system descriptor area You can assign values for items for which you are providing a description such as parameters in a WHERE clause or you can modify values for items that have been described by the database server during a DESCRIBE statement Syntax 1 355 SET DESCRIPTOR Figure 1 11 1 356 Syntax Setting the TYPE Field Use the set of codes shown in the following table to set the value of TYPE for each item SQL Data Type Integer Value CHAR 0 SMALLINT 1 INTEGER 2 FLOAT 3 SMALLFLOAT 4 DECIMAL 5 SERIAL 6 DATE 7 MONEY 8 DATET
241. applies privilege checking rules for a DBA For more information about privileges on stored procedures see Chapter 14 of the Informix Guide to SQL Tutorial Cascading Triggers 1 130 Syntax The database server allows triggers to cascade meaning that the triggered actions of a trigger can activate another trigger The maximum number of triggers in a cascading sequence is 61 the initial trigger plus a maximum of 60 cascading triggers When the number of cascading triggers in a series exceeds the maximum the database server returns error number 748 as shown in the following example Exceeded limit on maximum number of cascaded triggers The following example illustrates a series of cascading triggers that enforce referential integrity on the manufact stock and items tables in the stores6 database When a manufacturer is deleted from the manufact table the first trigger del_manu deletes all the manufacturer s items from the stock table Each delete in the stock table activates a second trigger del_items that deletes all the manufacturer s items from the items table Finally each delete in the items table triggers the stored procedure log_order which creates a record of any orders in the orders table that can no longer be filled CREATI F F RIGGER del_manu E T DELETE ON manufact REFERENCING OLD AS pre_del FOR EACH ROW DELETE FROM stock WHERE manu_code pre_del manu_code CREATE TRIGGER del_stock
242. are keywords they must be qualified by the owner name for exam ple owner insert update If the owner name table name and column name are all keywords the owner name must be in quotes for example delete insert update The only exception is when these keywords are the first table or column name in the list then you do not have to qualify them For example delete in the following statement does not need to be qualified because it is the first column listed in the INTO clause CREATE TRIGGER t1 UPDATE OF b ON tabl FOR EACH ROW EXECUTE PROCEDURE p2 INTO delete d Syntax 1 123 CREATE TRIGGER The following examples show instances where you must qualify the column name or the table name CRI Ww EATI E TRIGGER t1 INSERT ON tabl EFORE INSERT INTO tab2 SELECT FROM tab3 ownerl update FROM clause of a SELECT statement CRI E EATI E TRIGGER t3 UPDATE OF b ON tabl OR EACH ROW EXECUTE PROCEDURE p2 INTO d tabl delete INTO clause of an EXECUTE PROCEDURE statement CRI nj wW EATI E TRIGGER t4 DELETE ON tabl EFORE INSERT INTO tab3 SELECT deptno SUM exp ROM budget GROUP BY deptno budget update GROUP BY clause of a SELECT statement CRI w EATI E TRIGGER t2 UPDATE OF a ON tabl EFORE UPDATE tab2 SET a 10 tab2 insert 5 SET clause of an UPDATE statement Using Correlation Names in Trigger
243. ariable name that contains the descriptor a quoted string being allocated The descriptor variable must conform to the same rules as any identifier as described in the Identifier segment on page 1 469 occurrences is the number of items that can be held by the system descriptor area An unsigned INTEGER that specifies a value greater than 0 default 100 occurrences variable is a host variable that contains the number of occurrences The ALLOCATE DESCRIPTOR statement creates a system descriptor area that is identified by descriptor or descriptor variable A system descriptor area contains one or more item descriptors Each item descriptor holds a data value that can be sent to or received from the database server The item descriptors also contain information about the database such as type length scale precision nullability and so on Syntax 1 9 ALLOCATE DESCRIPTOR The occurrences or occurrences variable specifies the number of item descriptors desired in the system descriptor or descriptor variable Initially all fields in the item descriptor area are undefined The COUNT is set to the number of occurrences specified The TYPE LENGTH and other infor mation in the item descriptor are set when a DESCRIBE statement is executed using the system descriptor The DESCRIBE statement also allocates memory for the DATA field in each item descriptor based on the TYPE and LENGTH information The item descriptors can be used with des
244. ascading deletes feature is that it allows you to reduce the quantity of SQL statements you need to use to perform delete actions The ON DELETE CASCADE option is not available in INFORMIX SE databases For example the stock table contains the stock_num column as a primary key The catalog table refers to the stock_num column as a foreign key The following ALTER TABLE statements drop an existing foreign key constraint without cascading delete and add a new constraint that specifies cascading deletes ALTER TABLE catalog DROP CONSTRAINT aa ALTER TABLE catalog ADD CONSTRAINT FOREIGN KEY stock _num manu_code REFERENCES stock ON DELETE CASCADE CONSTRAINT ab With cascading deletes specified on the child table in addition to deleting a stock item from the stock table the delete cascades to the catalog table asso ciated with the stock_num foreign key Of course this works only if the stock_num that you are deleting has not been ordered otherwise the con straint from the items table disallows the cascading delete For more informa tion see the following section What Happens to Multiple Child Tables You specify cascading deletes with the REFERENCES clause on the ADD CONSTRAINT clause You only need the References privilege to indicate cas cading deletes You do not need the Delete privilege to specify cascading deletes in tables however you do need Delete privilege on tables referenced in
245. ases You can use the CURRENT OF clause with any select cursor References See the INSERT UPDATE DECLARE GET DIAGNOSTICS and FETCH statements in this manual In the Informix Guide to SQL Tutorial see the discussions of cursors and data modification in Chapter 5 and Chapter 6 respectively Syntax 1 161 DESCRIBE DESCRIBE Purpo se Use the DESCRIBE statement to obtain information about a prepared statement before you execute it The DESCRIBE statement returns the pre pared statement type and for a SELECT EXECUTE PROCEDURE or INSERT statement the number data types and size of the values and the name of the column or expression returned by the query The information can be stored in a system descriptor area or in ESQL C in an sqlda structure Syntax a Usage 1 162 Syntax USING DESCRIBE a ae Jea SQL DESCRIPTOR descriptor statement l descriptor id variable variable descriptor descriptor variable sqlda pointer statement id statement id variable INTO sqida pointer is a quoted string that identifies an allocated system descriptor area is an embedded variable name that identifies an allocated system descriptor area points to an sqlda structure is the identifier for a data structure that represents a prepared statement See the PREPARE statement on page 1 273 is an embedded variable name that identifies a data struc ture that represents a prepared statemen
246. atabase and some do not You can use the FLUSH statement to write buffered rows to the database without adding a new row The CLOSE statement writes any remaining rows before it closes an insert cursor If the current database uses explicit transactions you must execute a PUT statement within a transaction The following example uses a PUT statement in INFORMIX ESQL C exec sql prepare ins_mcode from insert into manufact values exec sql declare mcode cursor for ins_mcode exec sql open mcode exec sql put mcode from the_code the_name PUT is not an X Open SQL statement Therefore you get a warning message if you compile a PUT statement in X Open mode in an ESQL product For details on compiling in X Open mode see your product manual Supplying Inserted Values The values that compose the inserted row can come from one of the following sources e Constant values written into the INSERT statement Program variables named in the INSERT statement e Program variables named in the FROM clause of the PUT statement e Values that are prepared in memory addressed by an sqlda structure or a system descriptor area and then named in the USING clause of the PUT statement Syntax 1 285 PUT Using Constant Values in INSERT The VALUES clause of the INSERT statement lists the values of the inserted columns One or more of these values might be constants that is numbers or character strings When all of the inse
247. atabase environment a deadlock condition can occur A deadlock condition occurs when one transaction obtains a lock on a table and a concurrent transaction tries to obtain a lock on the same table resulting in the application waiting for itself to release the lock CONNECT Database Environment Database Environment p dbname dbservername pathname db_env variable dbname 7 p ee dbname dbservername pathname dbname A dbservername pathname dbname dbservername db_env variable y is the name of the database to open is the name of the database server that is home to the database The dbservername must match the name of a database server in the sqlhosts file is the path of the database directory to the parent directory of the dbs directory the directory where INFORMIX SE database files reside is an ESQL C or ESQL COBOL character type host variable that contains a value representing a database environment This database environment can have any of the formats listed here that is dbname dbservername and so on Using these expressions you can specify either a server and a database a server only or a database only Specifying a Server Only The dbservername option establishes a connection to the named database server only it does not open a database When you use this option you must subsequently use the DATABASE CREATE DATABASE or START
248. atabase or add logging to an existing database These transaction logs can be buffered or unbuffered The default condition for transaction logs is unbuffered logging As soon as a transaction ends the INFORMIX OnLine Dynamic Server database server writes the transaction to the disk If a system failure occurs when you are using unbuffered logging you recover all completed transactions You gain a marginal increase in efficiency with buffered logging but you incur some risk In the event of a system failure the INFORMIX OnLine Dynamic Server database server cannot recover the completed transactions that were buffered in memory The SET LOG statement changes the transaction logging mode to unbuffered logging the SET BUFFERED LOG statement changes the mode to buffered logging The SET LOG statement redefines the mode for the current session only The default mode which the INFORMIX OnLine Dynamic Server administrator sets using the ON Monitor remains unchanged The buffering option does not affect retrievals from external tables For distributed queries a database with logging can retrieve only from databases with logging but it makes no difference whether the databases use buffered or unbuffered logging An ANSI compliant database cannot use buffered logs SET LOG References See the CREATE DATABASE and START DATABASE statements in this manual Syntax 1 373 SET OPTIMIZATION SET OPTIMIZATION Purpose Use the SET
249. atalog tables only user informix can modify systables Informix strongly recommends that you do not update delete or alter any rows in them Modifying the system catalog tables can destroy the integrity of the database The following example uses the PUBLIC keyword to grant the Connect privilege on the currently active database to all users GRANT CONNECT TO PUBLIC GRANT Table Level Privileges Table Level Privileges PRIVILEGES y N N INSERT N DELETE N SELECT E T A S column N UPDATE A S column i J N REFERENCES A i column p J N INDEX A ALTER A As the owner of a table or as DBA you control access to the table through seven table level privileges Four privileges control access to the table data Select Insert Delete and Update The remaining three privileges are Index which controls index creation Alter which controls the ability to change the table definition or alter an index and References which controls the ability to place referential constraints on table columns The person who creates a table is its owner and receives all seven table level privileges Table ownership cannot be transferred to another user To use the GRANT statement list the privileges that you are granting to user If you are granting all table level privileges use the keyword ALL If you are granting the Select Update or
250. ate ment on page 1 284 for information about checking errors and counting inserted rows Syntax 1 267 OPEN USING Clause The USING clause is required when the cursor is associated with a prepared SELECT statement that includes placeholders See the PREPARE statement on page 1 273 You can supply values for these parameters in one of two ways Naming Variables in USING If you know the number of parameters to be supplied at run time and their data types you can define the parameters needed by the statement as host variables in your program You pass parameters to the database server by opening the cursor with the USING keyword followed by the names of the variables These variables are matched with the SELECT statement parameters in a one to one correspondence from left to right You cannot include indicator variables in the list of variable names To use an indicator variable you must include the SELECT statement as part of the DECLARE statement The following example illustrates the USING clause with the OPEN statement in an INFORMIX ESQL C code fragment o sprintf select_1 s s s s s select o order_num sum total price from orders o items i where o order_date gt and o customer_num and o order_num i order_num group by o order_num exec sql prepare statement_1l from select_1l exec sql declare q_curs cursor for statement_1 exec sql open q_curs using o_date c_num US
251. ault value for a column the default is null unless you include the NOT NULL keywords after the data type of the column In this case if the NOT NULL keywords are used no default value exists for the column and the column does not allow nulls When the table contains data however you cannot use the NOT NULL option when you add a column unless both NOT NULL and a default value other than null is specified nor can you specify that the new column has a unique or primary key constraint When you want to add a column with a unique constraint the table can con tain a single row of data when you issue the ALTER TABLE statement When you want to add a column with a NOT NULL or primary key constraint the table must be empty when you issue the ALTER TABLE statement The following statement is valid only if the items table is empty ALTER TABLE items ADD item_weight DECIMAL 6 2 NOT NULL BEFORE total_price New Column Constraint Definition New Column Constraint Definition DISTINCT lt PRIMARY 3 Constraint E CONSTRAINT Name p 1 419 REFERENCES NY Clause A p 1 21 O CHECK j Clause p 1 25 You cannot specify a unique or primary key constraint on a new column if the table contains data However in the case of a unique constraint the table can contain a single row of data When you want to add a column with a primary key constraint the table must be e
252. ay in the SELECT statement as the SQL functions USER CURRENT and TODAY Thus instead of returning josh 11 30 30 1 22 89 the SELECT statement returns the current user name the current time and the current date If you want to select the actual columns of the table you must write the SELECT statement in one of the following ways SELECT mytab user mytab current mytab today FROM mytab EXEC SQL SELECT FROM mytab Identifier Using Keywords as Column Names Using ALL Specific workarounds exist for using a keyword as a column name ina SELECT statement or other SQL statement In some cases there might be more than one suitable workaround DISTINCT or UNIQUE as a Column Name The first pair of examples shows a workaround for using the ALL DISTINCT or UNIQUE keyword in a SELECT statement Using all as a column name causes the following example to fail because the database server interprets all as a keyword rather than as a column name SELECT all FROM mytab fails The workaround in following example uses the keyword ALL with the column name all SELECT ALL all FROM mytab The rest of the examples in this section show workarounds for using the keywords UNIQUE or DISTINCT as a column name in a CREATE TABLE statement Using unique as a column name causes the following example to fail because the database server interprets unique as a keyword rather than as a column name CR
253. base If the num ber of rows affected by a single INSERT statement is quite large you can exceed the maximum number of simultaneous locks permitted To prevent this situation either insert fewer rows per transaction or lock the page or the entire table before executing the INSERT statement To prevent this situation either insert fewer rows per transaction or lock the entire table before executing the INSERT statement Syntax 1 249 INSERT VALUES Clause 1 250 Syntax VALUES Clause pe VALUES ESQL variable indicator variable variable name When you use the VALUES clause you can insert only one row at a time Each value that follows the VALUES keyword is assigned to the corresponding col umn listed in the INSERT INTO clause or in column order if a list of columns is not specified name indicator variable indicator variable TTT 4 DBSERVERNAME _ p 1 438 is a variable associated with a host variable that indicates when an ESQL statement returns a null value to that host variable is a program variable or host variable as defined in an SQL API NULL A Literal Number N p 1 493 Quoted String J p 1 497 USER joa A p 1 438 Literal DATETIME p 1 487 Literal INTERVAL J p 1 490 TODAY p 1 439 CURRENT p 1 440 ___ E SITENAME p 1 438 o INSERT If you are inserting a quoted string into a co
254. base server returns the precision and scale information for a column into the PRECISION and SCALE fields after a DESCRIBE statement is executed If the TYPE is not DECIMAL or MONEY the SCALE and PRECISION fields are undefined Using the VALUE Clause After a Fetch Each time your program fetches a row it must copy the fetched value into host variables so that the data can be used To accomplish this use a GET DESCRIPTOR statement after each fetch for each of the values in the select list If three values exist in the select list you need to use three GET DESCRIPTOR statements after each fetch assuming you want to read all three values The item numbers for each of the three GET DESCRIPTOR statements are 1 2 and 3 The following INFORMIX ESQL C example shows how you can copy the data out of the DATA field into a host variable result after a fetch For this example it is predetermined that all values returned are the same data type exec sql fetch democursor using sql descriptor demodesc if sqlca sqlcode 0 break for i 1 i lt desc_count i exec sql get descriptor demodesc value i result DATA printf s result printf n GET DESCRIPTOR The following INFORMIX ESQL COBOL example shows how you can copy the data out of the DATA field into host variables after a fetch The first use of GET DESCRIPTOR uses a literal item number the second GET DESCRIPTOR uses a host variable to hold the it
255. base specification empinfo personnel dbservername Option If you use a database server name do not put any spaces between the name and the For example the following statement is valid for the stores6 database on the training database server DATABASE stores6 training Specifying a database server name allows you to choose a database on another database server as your current database You can name the current database server using dbservername although that is extra information dbservername dbname Option 1 422 Syntax If you use the alternative naming method do not put spaces between the quotes slashes and names as shown in the following example DATABASE training stores6 As with the dbservername option specifying a database server name allows you to choose a database that is on another database server as your current database You can name the local database server by using dbservername along with the dbname Database Name variable name Option You can use a variable within an SQL API to hold the name of a database If you want to specify a database that neither resides in your current directory nor in a directory specified by the DBPATH environment variable you must follow the DATABASE keyword with a program variable that evaluates to the full pathname of the database excluding the dbs extension dbservernamelpathname dbname Option You can specify a database on a specifi
256. before the first executable statement in the body of the procedure 1 192 Syntax EXECUTE PROCEDURE If arguments are missing and do not have default values they are initialized to the value of UNDEFINED An attempt to use any variable that has the value of UNDEFINED results in an error Procedure arguments are bound to procedure parameters by name or position but not both That is you can use parameter name syntax for none or all of the arguments specified in one EXECUTE PROCEDURE statement For example both of the procedure calls are valid for a procedure that expects three character arguments t n and d as shown in the following example EXECUTE PROCEDURE add_col t customer d integer n newint EXECUTE PROCEDURE add_col customer newint integer If the EXECUTE PROCEDURE statement returns more than one row it must be enclosed within an SPL FOREACH loop or accessed through a cursor INTO Clause The host variable list is a list of the host variables that receive the returned values from a procedure call A procedure that returns more than one row must be enclosed in a cursor If you execute a procedure from within a procedure the list contains procedure variables If you prepare the EXECUTE PROCEDURE statement you must declare acursor and use the FETCH statement to retrieve any returned values References See the CREATE PROCEDURE DROP PROCEDURE GRANT and CALL statements in this manual I
257. ble If the database server you specify is not on line an error is returned CONNECT Only Database Specified If you specify only a database in your CONNECT statement not a database server the application obtains the name of a database server from the DBPATH environment variable The database server in the INFORMIXSERVER environment variable is always added in front of the DBPATH value specified by the user Set environment variables as shown in the following example setenv INFORMIXSERVER srvA setenv DBPATH srvB srvC The resulting DBPATH used by your application is shown in the following example scvA srvB srvC The application first establishes a connection to the database server specified by INFORMIXSERVER If the server is INFORMIX OnLine Dynamic Server it locates the database using parameters specified in the configuration file If the server is an SE server it searches the directory that you supply If you do not supply a directory path it searches in the current directory if the server is local or the login directory if the server is remote If the database does not reside on the default database server or if the default database server is not on line the application connects to the next database server in DBPATH In the previous example this would be srvB If a server in DBPATH is an SE server it can contain a directory path For example the DBPATH might be sxvvB srvC usr xy
258. bles rowids the CURRENT USER SITENAME DBSERVERNAME or TODAY functions or stored procedure calls You cannot create check constraints for columns across tables When you are using the ADD or MODIFY clause the check constraint cannot depend upon values in other columns of the same table The following example adds anew column unit_price to the items table and includes a check constraint that ensures that the value entered is greater than 0 ALTER TABLE items ADD unit_price MONEY 6 2 CHECK unit_price gt 0 To create a constraint that checks values in more than one column use the ADD CONSTRAINT clause The following example builds a constraint on the column added in the previous example However the check constraint now spans two columns in the table ALTER TABLE items ADD constraint CHECK unit_price lt total_price Syntax 1 25 ALTER TABLE DROP Clause 1 26 Syntax DROP Clause p DROP column name p L column name column name is the name of the existing column that you wish to drop When you drop a column all constraints placed on that column are dropped as described in the following list e All single column constraints are dropped e All referential constraints that reference the column are dropped e All check constraints that reference the column are dropped e If the column is part of a multiple column unique or primary key constraint the con
259. but it sets a return code in the SQLCODE field of the sqlca The name of the field in each product is indicated in the following table Product Field Name ESQL C sqlca sqlcode SQLCODE ESQL COBOL SQLCODE OF SQLCA The return code value is either negative or zero as described in the following list negative An error is detected in the SELECT statement OPEN zero The SELECT statement is valid If the SELECT statement is valid but no rows match its criteria the first FETCH statement returns a value of 100 SQLNOTFOUND which means no rows found Note When you encounter an SQLCODE error be aware that there may be a corresponding SQLSTATE error value Check the GET DIAGNOSTICS statement for information about how to get the SQLSTATE value and how to use the GET DIAGNOSTICS statement to interpret the SQLSTATE value The following example illustrates a simple OPEN statement in INFORMIX ESQL C exec sql declare s_curs cursor for select from orders exec sql open s_curs If you are working in a database with explicit transactions you must open an update cursor within a transaction This requirement is waived if you declared the cursor using the WITH HOLD keyword See the DECLARE state ment on page 1 145 Opening an Procedure Cursor When you open an procedure cursor the EXECUTE PROCEDURE statement is passed to the database server along with any values specified in the USING clause The values are passed as ar
260. by DESCRIBE 5 33T set by PUT FLUSH 6 11T sqida structure syntax in DESCRIBE 1 1625 in EXECUTE 1 1845 in FETCH 1 194S in OPEN 1 263S in PUT 1 2845 use in DESCRIBE 1 1645 in FETCH 1 201S in OPEN 1 269S in PUT 1 288S use with EXECUTE statement 1 186S SQLERRD array count of deleted rows 6 4T count of inserted rows 6 11T count of rows 6 14T description of 5 12T syntax of naming 5 11T SQLERROR keyword in the WHENEVER statement 1 398S SQLEXEC environment variable 4 41R sqlexecd 12 14T sqlhosts See INFORMIXDIR etc sqlhosts SQLNOTFOUND error conditions with EXECUTE statement 1 188S SQLRM environment variable 4 42R SQLRMDIR environment variable 4 43R SQLSTATE in databases that are not ANSI compliant 5 18T use with a cursor 5 21T SQLWARNING keyword in the WHENEVER statement 1 400S SORT function syntax in expression 1 444S use in expression 1 447S START DATABASE statement adding a transaction log 9 24T syntax and use 1 376S state table in stores6 database columns in A 6R Statement naming with NLS 1 15R SQL ANSI compliance and DBANSIWARN 4 15R SQL CONNECT and INFORMIXSERVER 4 37R SQL CREATE TABLE and COLLCHAR 4 46R SQL DESCRIBE and COLLCHAR 4 46R SQL editing and DBEDIT 4 18R SQL LOAD and DBDELIMITER 4 18R SQL SELECT and COLLCHAR 4 46R Index 41 42 Index SQL SELECT and LC_COLLATE 4 51R SQL UNLOAD and DBDELIMITER 4 18R SQL UPDATE STATISTICS and DBUPSPACE 4 30R Statement identifier associat
261. c database server Do not put spaces between the quotes slashes and names The following database name describes a stores6 database that resides on the business database server ousiness u acctng demo stores6 Syntax 1 423 Data Type Data Type Purpose Use the Data Type segment whenever you have to specify the data type of a column or value The Data Type segment is used in the following statements ALTER TABLE CREATE PROCEDURE CREATE TABLE 1 424 Syntax area ee CHAR CHARACTER N Data Type DECIMAL DEC NUMERIC N DATETIME DATETIME Field Qualifier p 1 428 A lt gt FLOAT A N DOUBLE PRECISION po s i INT NE INTERVAL INTERVAL Field Qualifier p 1 485 1 ME MONEY iS A precision E 16 Je Ba float precision ae ecision le MNE SERIAL j ke zi N SMALLINT SMALLFLOAT J A REAL E INFORMIX OnLine Dynamic Server Specific Data Types p 1 426 p Syntax 1 425 Data Type INFORMIX OnLine Dynamic Server Specific Data Types 1 426 Syntax INFORMIX OnLine Dynamic Server Specific Data Types u blobspace family name float precision maximum precision reserve scale TEXT J BYTE Da IN TABLE 5 blobspace N family name VARCHAR maximum SEE varcuar E howe ef 0 is the name of an exist
262. can also be created with the CREATE TEMP TABLE statement If the DBSPACETEMP environment variable is set for INFORMIX OnLine Dynamic Server temporary tables created with the INTO TEMP clause are located in the dbspaces specified in the DBSPACETEMP list You can also spec ify dbspace settings with the ONCONFIG parameter DBSPACETEMP If neither the environment variable or configuration parameter is set the default set ting is the root dbspace The settings specified for the DBSPACETEMP envi ronment variable take precedence over the ONCONFIG parameter DBSPACE TEMP and the default setting For more information about creating temporary tables see CREATE TABLE on page 1 84 For more information about the DBSPACETEMP environment variable see Chapter 4 of the Informix Guide to SQL Reference For more information about the ONCONFIG parame ter DBSPACETEMP see the INFORMIX OnLine Dynamic Server Administrator s Guide Temporary tables are located in whatever directory is specified in the DBTEMP environment variable setting or in the directory of the database that is the dbs directory The temporary table disappears when your program ends or when you issue a DROP TABLE statement on the temporary table If your database does not have logging or if it has logging and you created the temporary table without the WITH NO LOG keywords the temporary table disappears when you close the current database If you use the same query results mor
263. cannot define a DELETE trigger event on a table with a referential constraint that specifies ON DELETE CASCADE It is your responsibility to guarantee that the triggering statement returns the same result with and without the triggered actions See Action Clause on page 1 116 and Triggered Action List on page 1 121 for more information on the behavior of triggered actions If INFORMIX OnLine Dynamic Server is the database server a triggering statement from an external database server can activate the trigger As shown in the following example an insert trigger on newtab managed by dbserverl is activated by an INSERT statement from dbserver2 The trigger executes as if the insert originated on dbserverl Trigger on stores6 dbserverl newtab CREATE TRIGGER ins_tr INSERT ON newtab REFERENCING new AS post_ins FOR EACH ROW EXECUTE PROCEDURE nt_pct post_ins mc Triggering statement from dbserver2 INSERT INTO stores6 dbserverl newtab SELECT item_num order_num quantity stock_num manu_code total_price FROM items Note An insert trigger is set off by an insert to an external database table Trigger Events with Cursors If the triggering statement uses a cursor the complete trigger is activated each time the statement executes For example if you declare a cursor for a triggering INSERT statement each PUT statement executes the complete trig ger Similarly if a triggering UPDATE or DEL
264. case no default value exists for the column The following example cre ates the newitems table In newitems the column manucode does not have a default value nor does it allow nulls CREATE TABLE newitems newitem_num INTEGER manucode CHAR 3 NOT NULL promotype INTEGER descrip CHAR 20 If you designate a column as NOT NULL and no default value is specified you must enter a value into this column when you insert a row or update that column in a row If you do not enter a value the database server returns an error See Data Type on page 1 424 for more information 1 90 Syntax CREATE TABLE Column Level Constraint Definition Option Column Level Constraint Definition gt cN B UNIQUE 7 l i Se CONSTRAINT Constraint Name DISTINCT p 1 419 PRIMARY KEY A g N REFERENCES Clause p 1 94 CHECK z Clause p 1 98 Unlike the table level constraint definition option constraints at the column level are limited to a single column In other words you cannot create check unique primary or foreign key multiple column constraints For more information on the unique primary key and check constraints see the The Constraint Definition Option on page 1 92 The following example creates a simple table with a unique and a primary key constraint and names the two constraints created CREATE TABLE accounts
265. cedure If you provide a default value for a parameter that value is used if the procedure is called with fewer than the necessary arguments If you do not provide a default value for the parameter and the procedure is called with less than the necessary arguments the calling application receives an error Syntax 1 69 CREATE PROCEDURE Subset of SOL Data Types Allowed in the Parameter List The SQL Data Type subset includes all the SQL data types except SERIAL TEXT and BYTE For the complete syntax of all the SQL data types see page 1 424 To use a TEXT or BYTE type use the REFERENCES keyword as shown in the diagram on page 1 69 Referencing TEXT or BYTE Values Use the REFERENCES clause to specify that a parameter contains TEXT or BYTE data If you use the DEFAULT NULL option in the REFERENCES clause and you call the procedure without a parameter a null value is used RETURNING Clause RETURNING Clause SQL Data Type g gt RETURNING Subset p p 1 REFERENCES Ra TEXT A procedure can return zero or more values or sets of values A procedure that returns more than one set of values such as multiple rows from a table is a cursory procedure For example the first RETURNING clause shown in the following example can return zero or one value if it is not a cursory procedure if it is cursory it returns more than one row from a table and each returned row contains one value The second
266. ces are standard in SQL and are allowed in the statement text The comment ends at the end of the line or at the end of the statement e The text can contain either a single SQL statement or a sequence of statements separated by semicolons Syntax 1 275 PREPARE Names of host language variables are not recognized as such in prepared text The only identifiers that you can use are names defined in the data base such as names of tables and columns Therefore you cannot prepare a SELECT statement that contains an INTO clause because the INTO clause requires a host language variable Use a question mark as a placeholder to indicate where data is supplied when the statement executes The text cannot include an embedded SQL statement prefix or terminator such as a dollar sign or the words EXEC SQL The following example shows a PREPARE statement in INFORMIX ESOL C exec sql prepare new_cust from insert into customer fname lname values Executing Stored Procedures Within a PREPARE Statement You can prepare an EXECUTE PROCEDURE statement in conjunction with the ALLOCATE DESCRIPTOR and GET DESCRIPTOR statements in an ESQL C pro gram Parameters to the stored procedure can be passed in the same manner as SELECT and may be passed at runtime or compile time See Chapter 14 of the Informix Guide to SQL Tutorial for information about creating and executing stored procedures See Chapter 10 of the INFORMIX
267. ces See the COMMIT WORK and ROLLBACK WORK statements in this manual In the Informix Guide to SQL Tutorial see the discussion of transactions and locking in Chapter 4 and Chapter 7 respectively 1 36 Syntax CHECK TABLE CHECK TABLE Purpose Syntax Usage Use the CHECK TABLE statement to compare the data in a table with its indexes to determine whether they match Use this statement when you think the data or the indexes might be corrupted because of a power failure computer crash or other abnormal program interruption Table CHECK TABLE Name c p 1 506 Specify the name of the database table for which you want to check the data and associated indexes as shown in the following example CHECK TABLE cust_calls The CHECK TABLE statement calls the secheck utility See the INFORMIX SE Administrator s Guide for a full description of the secheck utility You cannot use the CHECK TABLE statement on a table unless you own it or have the DBA privilege You cannot use the CHECK TABLE statement on the system catalog table systables as it is always open Instead you can run the secheck utility from the operating system prompt You cannot use the CHECK TABLE statement on other system catalog tables unless you are user informix References See the REPAIR TABLE statement in this chapter In the INFORMIX SE Administrator s Guide see the discussion of the secheck utility in Chapt
268. ch the order was placed SELECT order_num MONTH order_date FROM orders WEEKDAY Function The WEEKDAY function returns an integer that represents the day of the week zero represents Sunday one represents Monday and so on The follow ing lists all the orders that were paid on the same day of the week which is the current day SELECT FROM orders WHERE WEEKDAY paid_date WEEKDAY CURRENT YEAR Function The YEAR function returns a four digit integer that represents the year The following example lists orders in which the ship_date is earlier than the beginning of the current year SELECT order_num customer_num FROM orders WHERE year ship_date lt YEAR TODAY Similarly because a DATE value is a simple calendar date you cannot add or subtract a DATE value with an INTERVAL value whose last qualifier is smaller than DAY In this case convert the DATE value to a DATETIME value EXTEND Function The EXTEND function adjusts the precision of a DATETIME or DATE value The expression cannot be a quoted string representation of a DATE value If you do not specify first and last qualifiers the default qualifiers are YEAR TO FRACTION 3 If the expression contains fields that are not specified by the qualifiers the unwanted fields are discarded Expression If the first qualifier specifies a larger that is more significant field than what exists in the expression the new fields are filled in with value
269. cific privilege that should be available to the user REVOKE ALL ON customer FROM PUBLIC GRANT ALL ON customer TO john cathy GRANT SELECT fname lname company city ON customer TO PUBLIC Database Level Privileges Database Level Privileges p CONNECT p RESOURCE DBA Only a user with the DBA privilege can grant or revoke database level privileges Three levels of database privileges control access These privilege levels are from lowest to highest Connect Resource and DBA To revoke a database privilege specify one of the keywords CONNECT RESOURCE or DBA in the REVOKE statement Because of the hierarchical organization of the privileges as outlined in the privilege definitions described later in this section if you revoke either the Resource or the Connect privilege from a user with the DBA privilege the statement has no effect If you revoke the DBA privilege from a user with the DBA privilege the user retains the Connect privilege on the database To deny database access to a user with the DBA or Resource privilege you must first revoke the DBA or the Resource privilege and then revoke the Connect privilege in a separate REVOKE statement Syntax 1 303 REVOKE 1 304 Syntax Similarly if you revoke the Connect privilege from a user with the Resource privilege the statement has no effect If you revoke the Resource privilege from a user the user retains the Connect pri
270. ck for exceptions To declare an SQLSTATE variable within your application use the following syntax EXEC SQL BEGIN DECLARE SECTION char SQLSTATE 6 EXEC SQL END DECLARE SECTION For an example of how to declare and use an SQLSTATE variable in a program see Using GET DIAGNOSTICS for Full Error Checking on page 1 228 In Chapter 5 of the Informix Guide to SQL Tutorial see the discussion about error code handling In addition refer to the error handling chapter of the SQL API that you want to use Syntax 1 221 GET DIAGNOSTICS The Statement Clause Cs st_var MORE NUMBER ROW_COUNT st_var is a host variable that receives status information about the most recent SQL statement The st_var variable receives information for the specified status field name The st_var variable data type must be the same as that of the requested field When retrieving count and overflow information GET DIAGNOSTICS can deposit the values the three statement fields into corresponding host vari able The host variable data type must be the same as that of the requested field These three fields are represented by the following keywords ESQL C ESQL COBOL Field Name Field Field Host Variable Host Variable Keyword Data Type Contents Data Type Data Type MORE Character Y or N char 2 PIC X 1 NUMBER Integer 1 to 35 000 int PIC S9 9 ROW_COUNT Integer 0 to 999 999 999 int
271. code 0 break for i 0 i lt demodesc gt sqld i switch demodesc gt sqlvar i sqltype case cchartype printf s Ss demodesc gt sqlvar i sqlname demodesc gt sqlvar i sqldata break case cinttype printf Ss d n demodesc gt sqlvar i sqlname int demodesc gt sqlvar i sqldata break And so forth for each type exec sql close d_curs exec sql free d_curs Free the data memory for i 0 i lt demodesc gt sqld i free demodesc gt sqlvar i sqldata printf Program Over n prsqlda sp struct sqlvar_struct sp printf type d n sp gt sqltype printf len Sd n sp gt sqllen printf data lx n sp gt sqldata printf ind lx n sp gt sqlind printf name lx n sp gt sqlname Preparing Sequences of Multiple SQL Statements You can execute several SQL statements as one action if you include them in the same PREPARE statement Multistatement text is processed as a unit actions are not treated sequentially Therefore multistatement text cannot include statements that depend on action that occurs in a previous statement Syntax 1 281 PREPARE 1 282 Syntax in the text For example you cannot create a table and insert values into that table in the same prepared block Avoid placing BEGIN WORK and COMMIT WORK statements with other statements in a multistatement prepare In most situations
272. cope of a statement identifier to the file in which it is executed you may preprocess all the files with the local command line option See your ESQL product manual for more information restrictions and performance issues when preprocessing with the local option Syntax 1 185 EXECUTE The sqlca Record and EXECUTE Following an EXECUTE statement the sqlca see your embedded language product manual can reflect two results The sqlca can reflect an error within in the EXECUTE statement For example sqlca is set for 100 when an UPDATE WHERE statement within a prepared object processes zero rows The sqlca can also reflect the success or failure of the executed statement USING Clause 1 186 Syntax E C The USING clause specifies values that are to replace question mark placeholders in the prepared statement Providing values in the EXECUTE statement that replace the placeholders in the prepared statement is sometimes called parameterizing the prepared statement You can specify any of the following items to replace the question mark placeholders in a statement before you execute it e A host or program variable name if the number and data type of the question marks are known at compile time e A system descriptor that identifies a system e A descriptor that is a pointer to an sqlda structure Supplying Parameters Through Host or Program Variables You must supply one variable name for each placeholde
273. cribed stored proce dures See Chapter 2 SPL Statements for more information about stored procedures When a descriptor or descriptor variable with the same name is already allocated the system returns an error The WITH MAX Clause 1 10 Syntax You can use the optional WITH MAX occurrences clause to indicate the number of value descriptors you need This number must be greater than zero When the WITH MAX clause is not specified a default value of 100 is used for occurrences The following examples show the ALLOCATE DESCRIPTOR statement for two programming languages All show the WITH MAX occurrences clause In each pair the first example uses an embedded variable name and the second example uses a quoted string to identify the system descriptor area allocated The WITH MAX occurrences clause alternately uses an embedded variable name and the unsigned INTEGER 3 exec sql allocate descriptor descname with max occ exec sql allocate descriptor descl with max 3 INFORMIX ESQL C EXEC SQL ALLOCATE DESCRIPTOR DESCNAME WITH MAX OCC END EXEC EXEC SQL ALLOCATE DESCRIPTOR DESC1 WITH MAX 3 END EXEC INFORMIX ESQL COBOL ALLOCATE DESCRIPTOR References See the DEALLOCATE DESCRIPTOR DECLARE DESCRIBE EXECUTE FETCH GET DESCRIPTOR OPEN PREPARE PUT and SET DESCRIPTOR statements in this manual Syntax 1 11 ALTER INDEX ALTER INDEX Purpose Syntax Usage Use the ALTER INDE
274. ct cursor definition of 1 1485 opening 1 264S 5 20T reopening 1 2675 use of 1 1485 5 20T SELECT keyword ambiguous use as procedure variable 1 480S syntax in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 3025 Select list display label 2 49T expressions in 2 46T functions in 2 53T to 2 66T labels in 3 48T selecting all columns 2 12T selecting specific columns 2 18T specifying a substring in 2 27T Select privilege column level 11 10T definition of 1 236S 11 8T with a view 11 27T SELECT statement active set 2 29T aggregate functions in 1 4625 2 53T alias names 2 79T and COLLCHAR environment variable 4 46R and LC_COLLATE environment variable 4 51R and NLS collation order 1 15R as an argument to a stored procedure 2 4S assigning values with 14 21T associating with cursor with DECLARE 1 148S BETWEEN condition 1 327S column numbers 1 339S compound query 3 43T cursor for 5 19T 5 20T date oriented functions in 2 56T describing returned values with DESCRIBE 1 162S description of advanced 3 4T to 3 55T description of simple 2 3T to 2 83T display label 2 49T DISTINCT keyword 2 19T embedded 5 13T to 5 16T for joined tables 2 69T to 2 83T for single tables 2 11T to 2 66T FROM Clause 1 323S functions 2 53T to 2 66T GROUP BY clause 1 334S 3 4T HAVING clause 1 336S 3 9T IN condition 1 327S in FOR EACH ROW section 1 1175 in modifiable view 11 24T INTO clause with ESQL 1 318
275. ction that is tables columns and stored procedures must exist when the CREATE TRIGGER statement is executed This applies only to objects that are referenced directly in the trigger definition Syntax 1 121 CREATE TRIGGER The WHEN Condition The WHEN condition lets you make the triggered action dependent on the outcome of a test When you include a WHEN condition in a triggered action if the triggered action evaluates to true the actions in the triggered action list execute in the order in which they appear If the WHEN condition evaluates to false or unknown the actions in the triggered action list are not executed If the triggered action is in a FOR EACH ROW section its search condition is evaluated for each row For example the triggered action in the following trigger executes only if the condition in the WHEN clause is true CREATE TRIGGER up_price UPDATE OF unit_price ON stock REFERENCING OLD AS pre NEW AS post FOR EACH ROW WHEN post unit_price gt pre unit_price 2 INSERT INTO warn_tab VALUES pre stock_num pre order_num pre unit_price post unit_price CURRENT Triggered action with optional WHEN condition A stored procedure that executes inside the WHEN condition carries the same restrictions as a stored procedure that is called in a data manipulation state ment See CREATE PROCEDURE on page 1 68 for more information about a stored procedure that is called within a data
276. ction_name The only restriction on this is that an application can establish only one connection to each local server that uses the shared memory connection mechanism To find out whether a local server uses the shared memory connection mecha nism or the local loopback connection mechanism you should examine the INFORMIX etc sqlhosts file See the INFORMIX OnLine Dynamic Server Administrator s Guide for more information Only one connection is current at any time other connections are dormant The application cannot interact with a database through a dormant connec tion When an application establishes a new connection that connection becomes current and the previous current transaction becomes dormant You can make a dormant connection current with the SET CONNECTION statement See SET CONNECTION on page 1 346 Connection Identifiers The optional connection_name is a unique identifier that an application can use to refer to a connection in subsequent SET CONNECTION and DISCON NECT statements If the application does not provide a connection_name or a conn_nm host variable it can refer to the connection using the database envi ronment If the application makes more than one connection to the same database environment however each connection must have a unique connection_name After you associate a connection_name with a connection you can refer to the connection using only that connection_name Connection Context
277. current database If you issue a DROP TABLE statement you are not prompted to verify that you want to delete an entire table You cannot use a ROLLBACK WORK statement to undo a DROP TABLE state ment If you roll back a transaction that contains a DROP TABLE statement the table is not re created and you do not receive an error message Syntax 1 179 DROP TABLE The following example deletes two tables Both tables are within the current database and owned by the current user DROP TABLE customer DROP TABLE stores6 accntg joed state Reference See the CREATE TABLE and DROP DATABASE statements in this manual In the Informix Guide to SQL Tutorial see the discussions of data integrity and creating a table in Chapter 4 and Chapter 9 respectively 1 180 Syntax DROP TRIGGER DROP TRIGGER Purpose Syntax Usage Use the DROP TRIGGER statement to remove a trigger definition from the database _ DB E C Trigger DROP TRIGGER Name ed p 1 113 You must be the owner of the trigger or have the DBA privilege to drop a trigger Dropping a trigger removes the text of the trigger definition and the executable trigger from the database The following statement drops the items_pct trigger DROP TRIGGER items_pct You cannot drop a trigger inside a stored procedure if the procedure is called within a data manipulation statement For example in the following INSERT statement a
278. cutes or the cursor is closed subtract the third field of the SQLERRD array from pending Syntax 1 205 FLUSH References See the CLOSE DECLARE OPEN and PUT statements in this manual For information about SQLCA see your SQL API manual In the Informix Guide to SQL Tutorial see the discussion of FLUSH in Chapter 6 1 206 Syntax FREE FREE Purpose Syntax Usage The FREE statement releases resources that are allocated to a prepared statement or to a cursor ESQL BaL FREE cursor id cursor variable statement id statement id variable cursor id is the identifier of a cursor that you declared for a SELECT or INSERT statement cursor variable is an embedded variable name that identifies a cursor that you declared for a SELECT or INSERT statement statement id is the identifier of an SQL statement that you prepared with the PREPARE statement statement is an embedded variable name that identifies an SQL state id variable ment that you prepared with the PREPARE statement The FREE statement releases the resources allocated for a prepared statement or a declared cursor in the application development tool and the database server Resources are allocated when you prepare a statement or when you open a cursor see the DECLARE and OPEN statements on pages 1 145 and 1 263 respectively The sum of the number of open cursors and the number of prepared statements that you can have at one time in one proc
279. d customer numbers for which the order has not been paid SELECT order_num customer_num FROM orders WHERE paid_date IS NULL LIKE or MATCHES Condition For a complete description of the LIKE or MATCHES condition see page 1 409 The LIKE or MATCHES condition is satisfied when the column value meets the criteria specified in the quoted string The following SELECT statement returns all the columns in the customer table from each row in which the Iname column begins with the literal string Baxter Because the string is a literal string the condition is case sensitive SELECT FROM customer WHERE lname LIKE Baxter The following examples use the LIKE condition with a wildcard The first SELECT statement finds all stock items that are some kind of ball The second SELECT statement finds all company names that contain a percent sign The backslash is used as the standard escape character for the wildcard per cent sign The third SELECT statement uses the ESCAPE option with the LIKE condition to retrieve rows from the customer table in which the com pany column includes a percent sign The z is used as an escape character for the wildcard percent sign SELECT stock_num manu_code FROM stock WHERE description LIKE ball SELECT FROM customer WHERE company LIKE SELECT FROM customer WHERE company LIKE z ESCAPE z NLS SELECT The following examples use M
280. d 5 3T languages available 5 4T See also ESQL End of data signal in SQLCODE 5 11T 5 17T signal only for SELECT 6 14T when opening cursor 5 20T Entity attributes associated with 8 15T business rules 8 5T criteria for choosing 8 7T defined 8 4T important qualities of 8 5T in telephone directory example 8 7T integrity 4 18T naming 8 4T represented by a table 8 22T Entity occurrence defined 8 16T Entity relationship diagram connectivity 8 17T discussed 8 17T meaning of symbols 8 17T reading 8 18T ENVIGNORE environment variable 4 30R relation to chkenv utility 5 4R Environment configuration file debugging with chkenv 5 4R example 4 4R where stored 4 5R Environment variable and case sensitivity 4 6R ARC_DEFAULT 4 14R ARC_KEYPAD 4 14R COLLCHAR 4 45R DBANSIWARN 4 15R DBAPICODE 4 47R DBAPICODE and crtcmap utility 5 5R DBDATE 4 16R DBDELIMITER 4 18R DBEDIT 4 18R DBLANG 4 19R DBLANG and crtcmap utility 5 5R DBMONEY 4 20R DBNLS 4 48R DBPATH 4 21R 12 14T DBPRINT 4 24R DBREMOTECMD 4 25R DBSPACETEMP 4 26R DBTEMP 4 27R DBTIME 4 27R DBUPSPACE 4 30R default assumptions 4 6R defining in environment configuration file 4 4R definition of 4 3R ENVIGNORE 4 30R ENVIGNORE and chkenv utility 5 4R how to set in Bourne shell 4 5R how to set in C shell 4 5R how to set in Korn shell 4 5R INFORMIX environment variables listing 4 8R NFORMIXC 4 31R NFORMIXCOB 4 32R NFORMIXCOBDIR 4 32R NFORMIXCOBSTORE 4 33R NFORMI
281. d by the prepared statement The EXECUTE statement passes a prepared SQL statement to the database server for execution If the statement contained question mark placeholders specific values are supplied for them before execution Once prepared an SQL statement can be executed as often as needed You can execute any prepared statement except a prepared SELECT statement or prepared EXECUTE PROCEDURE statement for procedures that return rows A prepared SELECT statement returns rows of data you may use the DECLARE OPEN and FETCH cursor statements to retrieve the data rows You can however use EXECUTE on a prepared SELECT INTO TEMP state ment If you prepared an EXECUTE PROCEDURE statement and the proce dure returns rows you need to use DECLARE OPEN and FETCH as you would with a SELECT statement If you create or drop a trigger after you prepared a triggering INSERT DELETE or UPDATE statement the prepared statement returns an error when you execute it The following example shows an EXECUTE statement within an INFORMIX ESQL C program exec sql prepare del_l from delete from customer where customer_num 119 exec sql execute del_l A program can consist of one or more source code files By default the scope of a statement identifier is global to the program This means that a statement identifier created in one file can be referenced from another file In a multiple file program if you want to limit the s
282. d when the following situations occur A CONNECT statement successfully executes A SET CONNECTION statement successfully executes A DISCONNECT statement successfully executes at the current connection A DISCONNECT ALL statement fails When CONNECTION_NAME is not Updated The CONNECTION_NAME field is not updated when the following situations occur A CONNECT statement fails A DISCONNECT statement fails Note This does not include the DISCONNECT ALL statement A SET CONNECTION statement fails Note The CONNECTION_NAME field retains the value set in the previous SQL statement If any of the preceding conditions occur on the first SQL statement that executes the CONNECTION_NAME field is blank The Contents of the CONNECTION_NAME Field The CONNECTION_NAME field contains different information after you execute the following statements CONNECT the CONNECTION_NAME field contains the name of the connection specified in the CON NECT statement to which you connect or fail to connect The CONNECTION_NAME field is Syntax 1 227 GET DIAGNOSTICS blank if you do not have a current connection or if you make a default connection SET CONNECTION the CONNECTION_NAME field contains the name of the connection specified in the CON NECT statement to which you switch or fail to switch DISCONNECT the CONNECTION_NAME field contains the name of the connection specified in the CON NECT statement from which you
283. database and drop the connection References See the CONNECT DISCONNECT and DATABASE statements in this manual 1 348 Syntax SET CONSTRAINTS SET CONSTRAINTS Purpose Syntax Usage Use the SET CONSTRAINTS statement to check constraints at the transaction level if deferred or at the end of the statement if immediate SET EME CONSTRAINTS ALE IMMEDIATE y DEFERRED Constraint Name y 19 p 1 4 You can set constraints in a database only with logging The default constraint checking mode is IMMEDIATE When the SET CONSTRAINTS state ment is set to IMMEDIATE effective checking is turned on and all specified constraints are checked at the end of each INSERT UPDATE or DELETE statement If a constraint error occurs the statement is not executed When you set the SET CONSTRAINTS statement to DEFERRED effective checking is turned off and all specified constraints are not checked until the transaction is committed If a constraint error occurs while the transaction is being committed the transaction rolls back The duration of the SET CONSTRAINTS statement is the transaction in which itis executed You cannot execute the SET CONSTRAINTS statement outside a transaction Once a COMMIT or ROLLBACK WORK statement is successfully completed the constraint mode of all constraints reverts to IMMEDIATE To revert from deferred to effective checking you either can set the SET CONSTRAINTS to IMMEDIATE or u
284. database server are on the same machine the sqexplain out file is stored in your current directory When the current database is on another machine the sqexplain out file is stored in your home directory on the remote host If you do not have a home directory on the remote host the program stores sqexplain out in the directory from which the database server was started If you do not have write privileges to a directory INFORMIX SE generates an error SET EXPLAIN SET EXPLAIN Output The SET EXPLAIN output file contains a copy of the query a plan of execution that the database server optimizer selects and an estimate of the amount of work The optimizer selects a plan to provide the most efficient way to perform the query based on such things as the presence and type of indexes and the number of rows in each table The estimated cost is used by the optimizer compares the cost of one path with another The estimated cost does not translate directly into time How ever when data distributions are used it is generally true that a query with a higher estimate is likely to take longer to run than one with a smaller estimate The estimated cost of the query is included in the SET EXPLAIN output In the case of a query and a subquery two estimated cost figures are returned the query figure contains the subquery cost also The subquery cost is shown only so that you can see the cost associated with the subquery In addition to the
285. dcard character WHERE description LIKE oe es oe Condition MATCHES Option If you use the keyword MATCHES you can use the following wildcard characters in the quoted string matches zero or more characters matches any single character Pesca match any of the enclosed characters including character ranges asin a z A caret as the first character within the brackets matches any character that is not listed Hence abc matches any character that is not a b or c removes the special significance of the next character used to match or by writing or The following condition tests for the string tennis alone or in a longer string such as tennis ball or table tennis paddle WHERE description MATCHES tennis The following condition is true for the names Frank and frank WHERE fname MATCHES Ff rank The following condition is true for any name that begins with either an F or os LA WHERE fname MATCHES Ff ESCAPE with LIKE The ESCAPE clause lets you include an underscore _ or a percent sign in the quoted string and avoid having them be interpreted as wildcards If you choose to use z as the escape character the characters z_ in a string stand for the character _ Similarly the characters z represent the percent sign Syntax 1 411 Condition 1 412 Syntax Finally the characters zz in the stri
286. de matches an exception code in the list of error numbers The search through the list begins from the left and stops with the first match You can use a combination of an ON EXCEPTION statement without an IN clause and one or more ON EXCEPTION statements with an IN clause to set up a default trapping situation For example the sequence of statements in the following example has a net effect of saying Test for an error If itis error 210 211 or 212 take action A If it is error 300 take action B If it is any other error take action C Remember that when an error occurs the database server searches for the last declaration of the ON EXCEPTION statement that traps the particular error code SPL Statements 2 33 ON EXCEPTION CREATE PROCEDURE ex_test EXCEPTION ET error_num action C D EXCEPTION A E ee E O EXCEPTION IN 300 action B D EXCEPTION EXCEPTION IN 210 211 212 ET error_num action A D EXCEPTION Al nokhioad Receiving Error Information in the SET Clause If you use the SET clause when an exception occurs the SQL error number and optionally the ISAM code are inserted into the variables specified in the SET clause If you provided an error data variable any error text returned by the database server is put into the error data variable Error text includes such information as the offending table or column name Forcing Continuati
287. defined on page 1 430 that can be expression converted to an integer The HEX function returns the hexadecimal encoding of an integer expression The following example displays the data type and column length of the col umns of the orders table in hexadecimal format For MONEY and DECIMAL columns you can then determine the precision and scale from the lowest and next to the lowest bytes For VARCHAR and NVARCHAR columns you can determine the minimum space and maximum space from the lowest and next to the lowest bytes See Chapter 2 of the Informix Guide to SQL Reference for more information about encoded information SELECT colname coltype HEX collength FROM syscolumns C systables T WHERE C tabid T tabid AND T tabname orders Expression The following example lists the names of all the tables in the current database and their corresponding tblspace number in hexadecimal format This exam ple is particularly useful because the two most significant bytes in the hexa decimal number constitute the dbspace number and are used to identify the table in oncheck output SELECT tabname HEX partnum FROM systables The HEX function can operate on an expression as shown in the following example SELECT HEX order_num 1 FROM orders LENGTH Function LENGTH Function Quoted p BEG LENGTH String variable name column name Table Name p 1 506
288. disconnect or fail to disconnect If you disconnect and then you execute a DISCONNECT statement for a connection that is not current the CONNECTION_NAME field remains unchanged DISCONNECT ALL the CONNECTION_NAME field is blank if the statement executes successfully If the state ment does not execute successfully the CON NECTION_NAME field contains the names of all the connections specified in your CON NECT statement from which you did not dis connect However this does not mean the connection still exists The DATABASE Statement When you execute a DATABASE statement the CONNECTION_NAME field is blank Using GET DIAGNOSTICS for Full Error Checking 1 228 Syntax The following INFORMIX ESQL C example shows how to use a GET DIAGNOSTICS statement to return both statement and exception information This program executes several SQL statements A WHENEVER statement calls the error handling function sql_err when an SQLCODE error occurs Another WHENEVER statement calls the error handling function sql_err when an SQL WARNING occurs A switch statement is used within sql_err to determine if the SOLSTATE variable contains an SQLSTATE error code If an SQLSTATE error condition exists a GET DIAGNOSTICS statement is used to handle the error Note that lines 98 through 107 show you how to use the GET DIAGNOSTICS statement to diagnose both statement and exception information In addition these lines show you how to store the contents o
289. ditions are true when the total price is greater than the total price of at least one of the items in order number 1023 The first condition uses the ANY keyword the second uses the MIN aggregate function total_price gt ANY SELECT total_price FROM items WHERE order_num 1023 total_price gt SELECT MIN total_price FROM items WHERE order_num 1023 Using the NOT keyword with an ANY subquery tests whether an expression is not true for any subquery value The condition found in the following example of the NOT keyword with an ANY subquery is true when the expres sion total_price is not greater than any selected value That is it is true when total_price is greater than none of the total prices in order number 1023 NOT total_price gt ANY SELECT total_price FROM items WHERE order_num 1023 Condition Omitting ANY ALL or SOME Keywords You can omit the keywords ANY ALL or SOME in a subquery if you know that the subquery will return exactly one value If you omit the ANY ALL or SOME keywords and the subquery returns more than one value you receive an error The subquery in the following example returns only one row because it uses an aggregate function SELECT order_num FROM items WHERE stock_num 9 AND quantity SELECT MAX quantity FROM items WHERE stock_num 9 Conditions with AND or OR You can combine simple conditions with the logical operators AND or OR to form co
290. duplication or disclosure by the Government is subject to restrictions as set forth in subdivision c 1 ii of the Rights in Technical Data and Computer Software Clause at DFARS 252 227 7013 or subparagraphs c 1 and 2 of the Commercial Computer Software Restricted Rights at 48 CFR 52 227 19 as applicable and any other applicable license provisions set forth in the Government contract Copyright 1981 1994 by Informix Software Inc Preface The Informix Guide to SQL Syntax is intended to be used as a companion volume to the Informix Guide to SQL Tutorial and the Informix Guide to SQL Reference Like the other books in this series this book is written for people who already know how to use computers and who rely on them in their daily work Whereas the Informix Guide to SQL Tutorial explains the philosophy and concepts behind relational databases and the Informix Guide to SQL Reference provides reference information this volume contains all of the Structured Query Language SQL and Stored Procedure Language SPL syntax diagrams You must have the following Informix software e An INFORMIX OnLine Dynamic Server database server or an INFORMIX SE database server The database server either must be installed on your machine or on another machine to which your machine is connected over a network e Either an Informix application development tool such as INFORMIX 4GL or an SQL application programming interface API s
291. e 08 003 Connection does not exist 08 004 Client unable to establish connection 08 006 Transaction rolled back 08 007 Transaction state unknown 08 S01 Communication failure OA 000 Feature not supported 0A 001 Multiple server transactions 21 000 Cardinality violation 21 S01 Insert value list does not match column list 21 S02 Degree of derived table does not match column list Syntax 1 219 GET DIAGNOSTICS Class Subclass Meaning 22 000 Data exception 22 001 String data right truncation 22 002 Null value no indicator parameter 22 003 Numeric value out of range 22 005 Error in assignment 22 012 Division by zero 22 019 Invalid escape character 22 024 Unterminated string 22 025 Invalid escape sequence 23 000 Integrity constraint violation 24 000 Invalid cursor state 25 000 Invalid transaction state 2D 000 Invalid transaction termination 26 000 Invalid SQL statement identifier 2E 000 Invalid connection name 28 000 Invalid user authorization specification 33 000 Invalid SQL descriptor name 34 000 Invalid cursor name 35 000 Invalid exception number 37 000 Syntax error or access violation in PREPARE or EXECUTE IMMEDIATE 3C 000 Duplicate cursor name 40 000 Transaction rollback 40 003 Statement completion unknown 42 000 Syntax error or access violation SO 000 Invalid name SO 001 Base table or view table already exists SO 002 Base table not
292. e check constraint cannot depend upon values in other columns of the table As shown in the following example the table acct_chk has two columns with check constraints CREATE TABLE acct_chk chk_id SERIAL PRIMARY KEY debit INTEGER REFERENCES accounts acc_num debit_amt MONEY CHECK debit_amt BETWEEN 0 AND 99999 credit INTEGER REFERENCES accounts acc_num credit_amt MONEY CHECK credit_amt BETWEEN 0 AND 99999 Both debit_amt and credit_amt are MONEY columns with values that must be between 0 and 99999 If however you wanted to test that both columns had the same value you cannot create the check constraint at the column level To create a constraint that checks values in more than one column you must define the constraint at the table level Defining Check Constraints at the Table Level When a check constraint is defined at the table level each column in the search condition must be a column in that table You cannot create a check constraint for columns across tables The next example builds the same table and columns as the previous example However the check constraint now spans two columns in the table CREATE TABLE acct_chk chk_id SERIAL PRIMARY KEY debit INTEGER REFERENCES accounts acc_num debit_amt MONEY credit INTEGER REFERENCES accounts acc_num credit_amt MONEY CHECK debit_amt credit_amt In this example the debit_amt and cred
293. e table enter a zero for a SERIAL column in the INSERT statement When a SERIAL column is set to zero the database server assigns the next highest value If you want to enter an explicit value into a SERIAL column specify the nonzero value after first verifying that the value does not duplicate one Syntax 1 251 INSERT already in the table If the SERIAL column is uniquely indexed or has a unique constraint and you try to insert a value that duplicates one already in the table an error occurs For more information about the SERIAL data type see Chapter 3 of the Informix Guide to SQL Reference Using Functions in the VALUES Clause You can insert the current date date and time login name of the current user or database server name of the current INFORMIX OnLine Dynamic Server database into a column The TODAY keyword returns the system date The CURRENT keyword returns the system date and time The USER keyword returns an eight character string containing the login account name of the current user The SITENAME or DBSERVERNAME keyword returns the data base server name on which the current database resides The following exam ple uses the CURRENT and USER keywords to insert a new row into the cust_calls table INSERT INTO cust_calls customer_num call_dtime user_id call_code call_descr VALUES 212 CURRENT USER L 2 days Inserting Nulls with the VALUES Clause 1 252 Syntax When you execute an INSERT sta
294. e 7 6T maximizing 10 32T 10 35T Repeatable Read isolation 1 3675 7 12T SERIAL values 9 7T table lock 7 7T Condition segment ALL ANY SOME subquery 1 415S boolean expressions 1 405S comparison condition 1 405S description of 1 404S join conditions 1 331S null values 1 405S relational operators in 1 407S subquery in SELECT 1 413S syntax 1 404S use of functions in 1 405S wildcards in searches 1 410S with BETWEEN keyword 1 408S with ESCAPE keyword 1 411S with EXISTS keyword 1 414S with IN keyword 1 408S with IS keyword 1 409S with MATCHES keyword 1 409S with NOT keyword 1 410S Configuring a database server 12 15T CONNECT keyword in GRANT 1 2325 in REVOKE 1 303S Connect privilege 1 2325 1 303S 11 6T CONNECT statement and INFORMIXSERVER environment variable 4 37R 1 46S connection context 1 45S connection identifiers 1 45S database environment 1 49S DEFAULT option 1 465 implicit connections 1 465 opening a database 12 16T syntax 1 445 use 1 44S USER clause 1 52S WITH CONCURRENT TRANSACTION option 1 475 CONNECT TO statement with concatenation operator 1 4325 Connecting to data 12 12T Index 7 8 Index Connection context 1 45S dormant 1 169S identifiers 1 45S setting the INFORMIXCONRETRY environment variable 4 34R setting the INFORMIXCONTIME environment variable 4 35R Connectivity in relationship 8 8T 8 11T 8 17T Constant expression in SELECT 1 314S inserting with PUT 1 2
295. e INTO clause declare a cursor for the prepared query open the cursor and then fetch the cursor into the program variable using the FETCH statement with an INTO clause Alternatively you can declare a cursor for the query without first preparing the query and include the INTO clause in the query when you declare the cursor Then open the cursor and fetch the cursor without using the INTO clause of the FETCH statement SELECT Using Array Variables with the INTO Clause If you use a DECLARE statement with a SELECT statement that contains an INTO clause and the program variable is an array element you can identify individual elements of the array with integer constants or with variables The value of the variable used as a subscript is determined when the cursor is declared so afterward the subscript variable acts as a constant The following INFORMIX ESQL C code example declares a cursor for a SELECT INTO statement using the variables i and j as subscripts for the array a After you declare the cursor the INTO clause of the SELECT statement is equivalent to INTO a 5 a 2 i 5 j 2 exec sql declare c cursor for select order_num po_num into a i J a j from orders where order_num 1005 and po_num 2865 You can also use program variables in the FETCH statement to specify an element of a program array in the INTO clause With the FETCH statement the program variables are evaluated at each fetch rather than when you d
296. e TYPE LENGTH NAME SCALE PRECISION and NULLABLE information is set and memory for DATA fields is allocated automatically After a DESCRIBE statement is executed the SCALE and PRECISION fields contain the scale and precision of the column respectively If SCALE and PRE CISION are set in the SET DESCRIPTOR statement and TYPE is set to DECIMAL DESCRIBE or MONEY the LENGTH field is modified to adjust for the scale and precision of the decimal value If TYPE is not set to DECIMAL or MONEY the values for SCALE and PRECISION are not set and LENGTH is unaffected INTO sqlda pointer Clause E C The INTO sqlda pointer clause lets you allocate memory for an sqlda structure and store its address in an sqlda pointer The DESCRIBE statement fills in the allocated mrory with descriptive information it sets the sqlda sqld variable to the number of values in the SELECT INSERT or EXECUTE PROCEDURE list The sqlda structure also contains an array of data descriptors sqlvar structures one for each value in the SELECT INSERT or EXECUTE PROCE DURE list After a DESCRIBE statement is executed the sqlda sqlvar structure has the TYPE LENGTH and NAME fields set The DESCRIBE statement allocates memory for an sqlda pointer once it is declared in a program However the application program must designate the storage area of the sqlvar sqldata fields This product does not support pointers to an sqlda structure it returns an error if you tr
297. e action clause when a REFERENCING clause is present BEFORE Actions The BEFORE triggered action or actions execute once before the triggering statement executes If the triggering statement does not process any rows the BEFORE triggered actions still execute because it is not yet known whether any row is affected FOR EACH ROW Actions 1 116 Syntax The FOR EACH ROW triggered action or actions execute once for each row that the triggering statement affects The triggered SQL statement executes after the triggering statement processes each row If the triggering statement does not insert delete or update any rows the FOR EACH ROW triggered actions do not execute CREATE TRIGGER AFTER Actions An AFTER triggered action or actions execute once after the action of the triggering statement is complete If the triggering statement does not process any rows the AFTER triggered actions still execute Actions of Multiple Triggers When an UPDATE statement activates multiple triggers the triggered actions merge Assume that taba has columns a b c and d as shown in the following example CREATE TABLE taba a int b int c int d int Next assume that you define trig1 on columns a and c and trig2 on columns b and d If both triggers have triggered actions that are executed BEFORE FOR EACH ROW and AFTER then the triggered actions are executed in the following sequence BEFORE action list for trigger a c BEF
298. e all occurrences of the privilege For example if two users grant the same privilege to a user then both of them must revoke the privilege If one grantor revokes the Syntax 1 301 REVOKE 1 302 Syntax privilege the user retains the privilege received from the other grantor The database server keeps a record of each table level grant in the syscolauth and systabauth system catalog tables If a table owner grants a privilege to PUBLIC the owner cannot revoke the same privilege from any particular user For example if the table owner grants the Select privilege to PUBLIC and then attempts to revoke the Select privilege from mary the REVOKE statement generates an error The Select privilege was granted to PUBLIC not to mary and therefore the privilege can not be revoked from mary ISAM error number 111 No record found refers to the lack of a record in either the syscolauth or systabauth system cat alog table that would represent the grant that the table owner now wants to revoke You can revoke table level privileges individually or in combination List the keywords that correspond to the privileges that you are revoking from user The keywords are described in the following list Note that unlike the GRANT statement you cannot qualify the Select Update or References priv ilege with a column name in a REVOKE statement That is you cannot revoke access on specific columns INSERT provides the ability to insert rows
299. e delimiter character UNLOAD TO cust out DELIMITER SELECT fname lname company city FROM customer References See the LOAD and SELECT statements in this manual 1 380 Syntax UNLOCK TABLE UNLOCK TABLE Purpose Syntax Usage Use the UNLOCK TABLE statement in a database without transactions to unlock a table that you previously locked with the LOCK TABLE statement UNLOCK TABLE Synonym Name p 1 504 You can lock a table if you own the table or if you have the Select privileges on the table either from a direct grant or from a grant to public You can only unlock a table that you locked You cannot unlock a table that was locked by another process Only one lock can apply to a table at a time The table name either is the name of the table you are unlocking or a synonym for the table Do not specify a view or a synonym of a view To change the lock mode of a table in a database without transactions you first unlock the table using the UNLOCK TABLE statement then issue a new LOCK TABLE statement The UNLOCK TABLE statement fails if it is issued within a transaction Table locks set within a transaction are released automatically when the transaction completes You should not issue an UNLOCK TABLE statement within an ANSI compliant database The UNLOCK TABLE statement fails if it is issued within a transaction and a transaction is always in effect in an ANSI compliant database
300. e following INFORMIX ESQL C examples show some uses of question mark placeholders exec sql prepare s3 from select from customer where state matches exec sql prepare inl from insert into manufact values sprintf up_query s s update customer set zipcode where current of zip_cursor exec sql prepare update2 from up_query You can use a placeholder only to supply a value for an expression You cannot use a question mark placeholder to represent an identifier such as a database name a table name or a column name PREPARE The following example segment of INFORMIX ESQL C code prepares a statement from a variable named demoquery The text in the variable includes one question mark placeholder The prepared statement is asso ciated with a cursor and when the cursor is opened the USING clause of the OPEN statement supplies a value for the placeholder exec sql begin declare section char queryvalue 6 char demoquery 80 exec sql end declare section exec sql database stores6 sprintf demoquery Ss Ss select fname lname from customer where lname gt exec sql prepare quid from demoquery exec sql declare democursor cursor for quid strcpy queryvalue C exec sql open democursor using queryvalue Preparing an INFORMIX ESQL C statement that receives values The USING clause is available in both OPEN for statements associated with a cu
301. e has dangling child records which violates referential integrity However when logging is turned back on subsequent deletes cascade Restriction on Cascading Deletes Cascading deletes can be used for most deletes The only exception is correlated subqueries In correlated subqueries the subquery or inner SELECT is correlated when the value it produces depends on a value pro duced by the outer SELECT statement that contains it When you have imple mented cascading deletes you cannot write deletes that use a child table in the correlated subquery You receive an error when you attempt to delete from a query that contains such a correlated subquery Locks Held When You Create a Referential Constraint When you create a referential constraint an exclusive lock is placed on the referenced table The lock is released after you finish with the ALTER TABLE statement or at the end of a transaction if you are altering a table ina database with transactions and you are using transactions ALTER TABLE CHECK Clause CHECK Clause SSS BE on be A check constraint designates a condition that must be met before data can be inserted into a column If a row evaluates to false for any of the check con straints defined on a table during an insert or update the database server returns an error Check constraints are defined using search conditions The search condition cannot contain subqueries aggregates host varia
302. e indicated where appropriate INFORMIX ESQLI C Version 6 0 INFORMIX ESQL COBOL Version 6 0 INFORMIX SE Version 6 0 INFORMIX OnLine Dynamic Server Version 6 0 INFORMIX OnLine Optical Version 6 0 INFORMIX TP XA Version 6 0 Introduction 3 Other Useful Documentation An additional product that uses information from this manual is the INFORMIX Gateway with DRDA Version 6 0 Other Useful Documentation You can refer to the following related Informix documents that complement this manual 4 Introduction A companion volume to the Syntax the Informix Guide to SQL Tutorial provides a tutorial on SQL as it is implemented by Informix products It describes the fundamental ideas and terminology that are used when planning using and implementing a relational database An additional companion volume to the Syntax the Informix Guide to SQL Reference provides reference information on the types of Informix databases you can create the data types supported in Informix products system catalog tables associated with the database environment vari ables and the SQL utilities This guide also provides a detailed description of the stores6 demonstration database and contains a glossary The SQL Quick Syntax Guide contains syntax diagrams for all statements and segments described in this manual You or whoever installs your Informix products should refer to the UNIX Products Installation Guide for you
303. e name of a column you want to index To create an index that applies to several columns enter a list of column names separated by commas All the columns you specify must belong to the same table percent indicates the percent to be used for FILLFACTOR Value between 1 and 100 inclusive temporary table is the name of the temporary table whose columns you want name to index For restrictions on the temporary table name see the Identifier segment on page 1 469 When you issue the CREATE INDEX statement the table is locked in exclusive mode If another process is using the table the database server cannot execute the CREATE INDEX statement and returns an error Only one index on a particular sequence of columns is allowed with the same ascending or descending order Syntax 1 63 CREATE INDEX MAB You cannot use a ROLLBACK WORK statement to undo a CREATE INDEX statement If you roll back a transaction that contains a CREATE INDEX statement the index remains and you do not receive an error message UNIQUE Option The following example creates a unique index CREATE UNIQUE INDEX c_num_ix ON customer customer_num This index prevents duplicates in the customer_num column A column with a unique index can have at most one null value The DISTINCT keyword is a synonym for the keyword UNIQUE so the following statement would accomplish the same task CREATE DISTINCT INDEX c_num_ix ON customer customer_
304. e of the AND the condition would be true Constraint Name Constraint Name Purpose Syntax Usage Use the Constraint Name syntax wherever you see a reference to a constraint name in a syntax diagram The Constraint Name segment appears in the following statements ALTER TABLE CREATE TABLE SET CONSTRAINTS peiie owner e database owner Be dbservername JS database is the name of the database in which the constraint resides owner is the user name of the owner of the constraint If you are using an ANSI compliant database you must use the owner convention for a constraint that you do not own If you use quotes owner appears exactly as typed dbservername is the name of the INFORMIX OnLine Dynamic Server that is home to database The at sign is a literal character that you must use to introduce the database server name The actual name of the constraint is an SQL identifier If you are creating a table the name of the constraint must be unique within a database Syntax 1 419 Constraint Name 1 420 Syntax If you are creating a table the combination owner name must be unique within a database The owner name is case sensitive In an ANSI compliant database if you do not use quotes around the owner name the name of the table owner is stored as uppercase letters For more information see the discussion of case sensitivity in ANSI compliant databases on page 1 508 Da
305. e restrictive privileges take precedence You can grant table level privileges on a table or on a view Privileges granted to users remain in effect until you cancel them with a REVOKE statement Only grantors can revoke the privileges that they previously granted You cannot use a ROLLBACK WORK statement to undo a GRANT statement that successfully executes If you roll back a transaction that contains a GRANT statement the privilege is not revoked and you do not receive an error message Database Level Privileges 1 232 Syntax Database Level Privileges CONNECT RESOURCE DBA When you create a database you alone have access to it The database remains inaccessible to other users until you as DBA grant database privileges Three levels of database privileges control access These privilege levels are from lowest to highest Connect Resource and DBA These privileges are associated with the following keywords CONNECT gives you the ability to query and modify data You can modify the database schema if you own the object you wish to modify Any user with the Connect privilege can perform the following functions Execute SELECT INSERT UPDATE and DELETE statements provided the user has the necessary table level privileges RESOURCE DBA GRANT Create views provided the user has the Select privilege on the underlying tables Create synonyms Create temporary tables and create indexes on
306. e than once a temporary table saves time In addition using an INTO TEMP clause often gives you clearer and more understandable SELECT statements However the data in the tempo rary table is static data is not updated as changes are made to the tables used to build the temporary table The column names of the temporary table are those named in the SELECT clause You must supply a display label for all expressions other than simple column expressions The display label for a column or expression becomes the column name in the temporary table If you do not provide a display label SELECT for a column expression the temporary table uses the column name from the select list The following example creates the pushdate table with two columns customer_num and slowdate SELECT customer_num call_dtime 5 UNITS DAY slowdate FROM cust_calls INTO TEMP pushdate You can put indexes on a temporary table INTO TEMP Clause and WHERE Clause When you use the INTO TEMP clause combined with the WHERE clause and no rows are returned the SQLNOTFOUND value is 100 in ANSI compliant databases and 0 in databases that are not ANSI compliant If the SELECT INTO TEMP WHERE is a part of a multistatement prepare and no rows are returned the SQLNOTFOUND value is 100 for both ANSI compliant databases and databases that are not ANSI compliant INTO TEMP Clause and INTO Do not use the INTO option with the INTO TEMP clause If you do no resul
307. e to SQL Tutorial see the discussion of the DESCRIBE statement in Chapter 5 For further information about how to use a system descriptor area or an sqlda pointer if you intend to use a FETCH USING DESCRIPTOR or an INSERT USING DESCRIPTOR statement refer to the manual for your SQL API 1 166 Syntax DISCONNECT DISCONNECT Purpose The DISCONNECT statement terminates a connection between an application and a database server Syntax BEJ DISCONNECT CURRENT 7 ESQL K DEFAULT KN ALL A hs connection name Me conn_nm variable oA connection name is a quoted string that identifies the connection It is the connection name assigned by the CONNECT statement when the initial connection was made conn_nm variable is an ESQL C or ESQL COBOL host variable that holds a character string that identifies the connection The value of conn_nm variable is the connection name assigned by the CONNECT statement when the initial connection was made Usage The DISCONNECT statement lets you terminate a connection to a database server If a database is open it closes before the connection drops Syntax 1 167 DISCONNECT 1 168 Syntax Use the keyword CURRENT to terminate the current connection For example the DISCONNECT statement in the following excerpt drops the current connection to the database server mydbsrvr CONNECT TO stores6 mydbsrvr DISCONNECT CURRENT When the DISCONNECT statement dro
308. e trigger event is a DELETE statement use of the new correlation name as a qualifier causes an error because the column has no value after the row is deleted See Using Correlation Names in Triggered Actions on page 1 124 for the rules governing the use of correlation names You can use the DELETE REFERENCING clause only if you define a FOR EACH ROW triggered action Syntax 1 119 CREATE TRIGGER UPDATE REFERENCING Clause 1 120 Syntax UPDATE REFERENCING Clause p gt __ REFERENCING A _ oLD correlation correlation name nu Fi name AS A NEW correlation ne vi name AS is a name you assign to an old or new column value so that you can refer to that value within the triggered action The old column value in the triggering table is its value before the triggering statement made the change its new value is its value after the triggering statement exe cutes Once you assign a correlation name you can use it only inside the FOR EACH ROW triggered action See Action Clause Referencing on page 1 121 The correla tion name follows the same syntax rules as other identifi ers See Identifier on page 1 469 The correlation name must be unique within the CREATE TRIGGER statement You use the correlation name to refer to an old or new column value by preceding the column name with the correlation name and a period For example if the new correlation name is post you refer to the new value fo
309. ecifying a DEBUG file to contain the output an error is generated The trace state is inherited by called procedures That is a called procedure assumes the same trace state ON OFF or PROCEDURE as the calling proce dure The called procedure can set its own trace state but that state is not passed back to the calling procedure The trace state is not inherited by a procedure that is executed on a remote database server 2 42 SPL Statements TRACE TRACE ON If you specify the keyword ON all statements are traced The values of variables in expressions or otherwise are printed before they are used Turn ing tracing ON implies tracing both procedure calls and statements in the body of the procedure TRACE OFF If you specify the keyword OFF all tracing is turned off TRACE PROCEDURE If you specify the keyword PROCEDURE only the procedure calls and return values are traced not the body of the procedure Printing Expressions You can use the TRACE statement with a quoted string or an expression to display values or comments in the output file If the expression is not a literal expression the expression is evaluated before being written to the output file You can use the TRACE statement with an expression even if you used a TRACE OFF statement earlier in a procedure However you must have established a trace output file using the SET DEBUG statement SPL Statements 2 43 TRACE The following example uses a
310. eclare the cursor Error Checking If the number of variables listed in the INTO clause differs from the number of items in the SELECT clause a warning is returned in the sqlwarn struc ture the specific structure name is shown in the following diagram The actual number of variables transferred is the lesser of the two numbers See your SQL API product manual for information about the sqlwarn structure Product Name Variable Name ESQL C sqica sqlwarn3 sqlwarn3 ESQL COBOL SQLWARN3 OF SQLWARN OF SQLCA If the number of variables listed in the INTO clause differs from the number of items in the SELECT clause you receive an error Syntax 1 321 SELECT If the data type of the receiving variable does not match that of the selected SPL item the data type of the selected item is converted if possible If the con version is impossible an error occurs and a negative value is returned in the status variable In this case the value in the program variable is unpredict able The specific name of the status variable for each application development tool is shown in the following table Product Name Variable Name ESQL C sqlca sqlcode SQLCODE ESQL COBOL SQLCODE OF SQLCA 1 322 Syntax SELECT FROM Clause The FROM clause lists the table or tables from which you are selecting the data The following diagram shows the syntax of the FROM clause
311. ect an accessible database as the current database Database a DATABASE Name j p 1 421 A Fi EXCLUSIVE You can use the DATABASE statement to select any database on your database server You can select a database on another OnLine database server by specifying the name of the database server with the database name Issuing a DATABASE statement when a database is already open closes the current database before opening the new one Closing the current database releases any cursor resources held by the database server which invalidates any cursors you have declared up to that point You cannot include the DATABASE statement in a multistatement PREPARE operation You can determine the type of database a user selects by checking the warning flag after a DATABASE statement in the sqlca structure If the database has transactions the second element of the sqlcawarn structure contains a W after the DATABASE statement executes See the following chart for the name of the variable used for each product Product Field Name ESQL C sqlca sqlwarn sqlwarn1 ESQL COBOL SQLWARN1 OF SQLWARN OF SQLCA ANSI ESQL DATABASE If the database is ANSI compliant the third element of the sqlcawarn structure contains a W after the DATABASE statement executes See the following chart for the name of the variable that each product uses Product Field Name ESQL C sqlca sqlwarn sqlwarn2 ESQL COBOL SQLWARN2 OF SQLWARN OF S
312. ected program stoppage Only damaged tables are rebuilt You can determine whether you need to use the REPAIR TABLE statement by first issuing the CHECK TABLE statement Table REPAIR TABLE Name p 1 506 fjs Specify the name of the table for which you want to restore the integrity of the index files as shown in the following example REPAIR TABLE cust_calls You cannot use the REPAIR TABLE statement on a table unless you own it or have the DBA privilege on the database You cannot use the REPAIR TABLE statement on the system catalog table systables unless you have the DBA privilege on the database The REPAIR TABLE statement calls the secheck utility References See the CHECK TABLE statement in this manual See the INFORMIX SE Administrator s Guide for a full description of secheck Syntax 1 299 REVOKE REVOKE Purpose Use the REVOKE statement to remove another user s privileges for a table database or procedure Syntax Table BEJE REVOKE _ Level Table Le Name ae FROM PUBLIC Privileges p 1 506 p 1 301 3 View Name user p 1 510 ee user Synonym Name p 1 504 Procedure EXECUTE ON Name p 1 495 Database Level J Privileges p 1 303 user names the user or users whose privileges are revoked The keyword PUBLIC revokes privileges from all users If you use quotes
313. ed Actions 1 124 Syntax The following rules apply when you use correlation names in triggered actions You can use the correlation names for the old and new column values only in statements in the FOR EACH ROW triggered action list You can use the old and new correlation names to qualify any column in the trig gering table in either the WHEN condition or the triggered SQL statements CREATE TRIGGER The old and new correlation names refer to all rows affected by the triggering statement e You cannot use the correlation name to qualify a column name in the GROUP BY the SET or the COUNT DISTINCT clause The scope of the correlation names is the entire trigger definition This scope is statically determined meaning that it is limited to the trigger def inition Thus it does not encompass cascading triggers or columns that are qualified by a table name in a stored procedure that is a triggered action When to Use Correlation Names In an SQL statement in a FOR EACH ROW triggered action you must qualify all references to columns in the triggering table with either the old or new cor relation name unless the statement is valid independent of the triggered action In other words if a column name inside a FOR EACH ROW triggered action list is not qualified by a correlation name even if it is qualified by the trigger ing table name it is interpreted as if the statement is independent of the triggered action No speci
314. ed from the stored procedure The database server performs the update immediately upon returning from the stored procedure See EXECUTE PROCEDURE on page 1 192 for more information about the statement e You cannot use the old or the new correlation name inside the stored procedure If you need to use the corresponding values in the procedure you must pass them as parameters The stored procedure should be inde pendent of triggers and the old or the new correlation name do not have any meaning outside the trigger 1 128 Syntax CREATE TRIGGER e You cannot use a BEGIN WORK COMMIT WORK ROLLBACK WORK or SET CONSTRAINTS statement When you use a stored procedure as a triggered action the objects that it references are not checked until the procedure is executed Privileges to Execute Triggered Actions If you are not the trigger owner but the trigger owner s privileges include the WITH GRANT OPTION privilege you inherit the owner s privileges as well as the WITH GRANT OPTION privilege for each triggered SQL statement You have these privileges in addition to your own privileges If the triggered action is a stored procedure you must have the Execute privilege on the procedure or the owner of the trigger must have the Execute privilege and the WITH GRANT OPTION privilege Inside the stored proce dure you do not carry the privileges of the trigger owner Instead you have the following privileges 1 The triggered ac
315. ed language product The DESCRIBE statement uses the SQLCODE field differently than any other statement possibly returning a nonzero value when it executes successfully You can revise standard error checking routines to accommodate this if desired Checking for Existence of a WHERE Clause If the DESCRIBE statement detects that a prepared statement contains an UPDATE or DELETE statement without a WHERE clause the DESCRIBE statement sets the following sqlca variable to W ESQL C sqlca sqlwarn sqlwarn4 ESQL COBOL SQLWARN4 OF SQLWARN OF SQLCA Without a WHERE clause the update or delete action is applied to the entire table By checking this variable you can avoid unintended global changes to your table Describing Values Returned by SELECT or EXECUTE PROCEDURE or Required for INSERT If the prepared statement text includes a SELECT statement without an INTO TEMP clause an EXECUTE PROCEDURE statement or an INSERT statement the DESCRIBE statement also returns a description of each column or Syntax 1 163 DESCRIBE expression included in the SELECT EXECUTE PROCEDURE or INSERT list These descriptions are stored in a system descriptor area or in a pointer to an sqida structure The description includes the following information e The data type of the column as defined in the table The length of the column in bytes e The name of the column or expression See Chapter 5 of the Informix Guide to SQL Tutorial for more
316. ed rows with FLUSH 1 2045 ROW keyword use in ALTER TABLE 1 338 use in CREATE TABLE 1 108S Row lock 7 8T Rowid locating internal row numbers 3 17T use in a column expression 1 435S use in a join 3 16T use in ORDER BY clause 1 3385 used as column name 1 474S Rowid function 13 18T ROWID keyword 1 435S Rules for stored procedures 1 1285 Run time program setting DBANSIWARN 4 15R setting INFORMIXCOBDIR 4 32R S SCALE field setting with SET DESCRIPTOR 1 3585 with GET DESCRIPTOR 1 214S Schema See Data Model Scroll cursor active set 5 25T definition of 1 149S 5 23T use of 1 149S with FETCH 1 196S with hold in a transaction 1 369S SCROLL keyword syntax in DECLARE 1 145S Index 37 38 Index use in DECLARE 1 1495 5 23T Search condition See Condition segment secheck utility 13 31T SECOND keyword syntax in DATETIME data type 1 428S in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 14R 1 491S Second normal form 8 31T Secondary site 12 20T Security constraining inserted values 11 20T 11 25T database level privileges 11 5T making database inaccessible 11 5T restricting access to columns 11 20T restricting access to rows 11 20T 11 21T restricting access to view 11 27T table level privileges 11 10T using host file system 11 4T using operating system facilities 11 4T with stored procedures 11 3T Seek time 13 17T Select description of 1 13T Sele
317. egment Naming conventions tables 12 16T Native Language Support See NLS Natural join 2 75T NCHAR data type description of 3 17R 9 15T syntax 1 425S versus CHAR data type 1 19R Nested ordering in SELECT 1 339S 2 15T Network computer 12 4T connection information 12 15T data sent over 13 21T performance of 13 20T simple model of 13 21T site 12 4T Network environment variable DBPATH 4 21R SQLRM 4 42R SQLRMDIR 4 43R NEW keyword in DELETE REFERENCING clause 1 119S in INSERT REFERENCING clause 1 118S in UPDATE REFERENCING clause 1 120S NEXT keyword syntax in FETCH 1 1945 use in FETCH 1 196S NEXT SIZE keywords specifying size of extents 10 8T use in CREATE TABLE 1 107S use in GRANT 1 2335 NLS 1 14R activating 2 25T activating in Informix products 1 16R and collation order 2 25T and dbexport utility 5 12R and dbimport utility 5 13R and MATCHES keyword 2 42T and ORDER BY keywords 2 25T 2 42T checking products for functionality 1 18R COLLCHAR environment variable 4 45R creating character mapping files for 5 5R data types for 1 19R database server compatibility 1 19R DBAPICODE environment variable 4 47R DBNLS environment variable 4 48R environment variables listed 4 9R error messages for incompatibility 1 21R functionality in Informix products 1 22R functionality listed 1 15R installation notes for language supplement 1 22R Index 29 N N N N N N N N N
318. eld qualifier to specify the units for an INTERVAL value The INTERVAL field qualifier is used in the Data Type segment Syntax a x YEAR ae y ee a TO YEAR 7 p a 4 Me MONTH precision TO MONTH A N DAY iS precision TO DAY A KN HOUR N precision TO HOUR A N MINUTE a poson J TO MINUTE A Ne SECOND N Ke wi TO SECOND A N FRACTION TO FRACTION oa op Syntax 1 485 INTERVAL Field Qualifier fiprecision is the maximum number of digits used in the fraction field The default is three the maximum is five precision is the number of digits in the largest number of months days hours or minutes that the interval can hold The default is two the maximum is nine y precision is the number of digits in the largest number of years that the interval can hold The default is four the maximum is nine Usage The examples in this section show INTERVAL data types that are of the type YEAR TO MONTH types The first example can hold an interval of up to 999 years and 11 months because it gives 3 as the precision of the year field The second example uses the default precision on the year field so it can hold an interval of up to 9 999 years and 11 months YEAR 3 TO MONTH YEAR TO MONTH When you want a value to contain only one field the first and last qualifiers are the same For example an interval of whole years is qualified as YEAR TO YEAR or YEAR 5 TO YEAR for an interval of up to 99
319. ely The Relational Operator segment is used in the Condition segment Syntax A relational operator takes the following form p lt p lt gt gt lt gt SSe lt means less than lt means less than or equal to gt means greater than means equal to gt means greater than or equal to lt gt means not equal to l means not equal to 1 500 Syntax Usage NLS Relational Operator For DATE and DATETIME expressions greater than means later in time For INTERVAL expressions greater than means a longer span of time For CHAR and VARCHAR expressions greater than means after in ASCII collat ing order where lowercase letters follow uppercase letters and both follow numerals The following chart contains the seven bit ASCII collating order Native language collating sequence is used for NCHAR and NVARCHAR expressions Syntax 1 501 Relational Operator Char Num Char 86 Num 43 44 45 46 47 48 49 50 51 Char A AA AB AC AD AE AF AG H AI J AK AL Num gt lt gt 87 88 89 90 91 92 93 94 95 52 96 97 98 99 53 54 55 56 10 11 12 13 14 15 16 17 18 19 20 M N O AP Q R AS AT AU AV 100 101 102 103 104 105 106 107 108 109 110 111 57 58 59 60 61 62 63 64 65 66 21 22 23 24 25 26 AW AX Y AZ esc A AN 67 68 69 70 71 112 113 27 28
320. em number EXEC SQL BEGIN DECLARE SECTION END EXEC 01 COUNT SQLINT 01 ITEMNO SQLINT 01 TYPE SQLINT 01 LENGTH SQLINT 01 LONGVAL SQLINT 01 CHVAL SQLCHAR 21 EXEC SQL END DECLARE SECTION END EXEC EXEC SQL GET DESCRIPTOR descl VALUE 1 TYPE TYPE LENGTH LENGTH CHVAL DATA END EXEC MOVE 2 TO ITEMNO EXEC SQL GET DESCRIPTOR descl VALUE ITEMNO TYPE TYPE LONGVAL DATA END EXEC Fetching a Null Value When you use GET DESCRIPTOR after a fetch and the fetched value is null then the INDICATOR field is set to 1 NULL The value of DATA is undefined if INDICATOR indicates a null value The host variable into which DATA is copied has an unpredictable value Using LENGTH or ILENGTH If your DATA or IDATA field contains a character string you must specify a value for LENGTH If you specify LENGTH 0 LENGTH is automatically set to the maximum length of the string The DATA or IDATA field may contain a literal character string or a character string derived from a character variable of type CHAR or VARCHAR This provides a method to dynamically determine the length of a string in the DATA or IDATA field If a DESCRIBE statement precedes a GET DESCRIPTOR statement LENGTH is automatically set to the maximum length of the character field specified in your table This information is identical for I LENGTH Syntax 1 215 GET DESCRIPTOR References 1 216 Syntax See the ALLOCATE DESCRIPTOR DEAL
321. ements DECLARE The result of a PREPARE statement is a statement identifier statement id or id variable which is a data structure representing the prepared statement text You declare a cursor for the statement text by associating a cursor with the statement id You can associate a sequential cursor with any prepared SELECT or EXECUTE PROCEDURE statement You cannot associate a scroll cursor with a prepared INSERT statement or with a SELECT statement that was prepared to include a FOR UPDATE clause After a cursor is opened used and closed a different statement can be prepared under the same statement id In this way it is possible to use a sin gle cursor with different statements at different times The cursor must be redeclared before you use it again The following example contains INFORMIX ESQL C code that prepares a SELECT statement and declares a cursor for the prepared statement text The statement id st_1 is first prepared from a SELECT statement that returns values then the cursor c_detail is declared for st_1 exec sql prepare st_1l from select order_date from orders where customer_num exec sql declare c_detail cursor for st_l If you want to modify data using a prepared SELECT statement add a FOR UPDATE clause to the statement text you wish to prepare as shown in the following INFORMIX ESQL C example exec sql prepare sel_l from select from customer for update exec sql declare sel_curs
322. ending order in SELECT 2 14T DESCRIBE statement and COLLCHAR environment variable 4 46R and the USING SQL DESCRIPTOR clause 1 164S describing statement type 1 163S 5 33T INTO sqlda pointer clause 1 165S relation to GET DESCRIPTOR 1 213S syntax 1 162S using with concatenation operator 1 432S values returned by SELECT 1 163S Descriptor 1 164S Determining ANSI compliance 1 10R Device optical 12 6T storage 12 6T Directory extension dbs 1 585 1 141S Dirty Read isolation level 1 3675 7 10T DIRTY READ keywords syntax in SET ISOLATION 1 366S DISCONNECT statement 1 169S ALL keyword 1 169S CURRENT keyword 1 1685 with concatenation operator 1 432S Disk access chunk 10 4T Index 15 16 Index cost to read a row 13 16T dbspace 10 4T latency of 13 17T nonsequential 13 18T nonsequential avoided by sorting 13 37T performance 13 17T to 13 19T 13 34T reducing contention 10 7T seek time 13 17T sequential 13 17T 13 34T sequential forced by query 13 32T 13 33T 13 35T using rowid 13 18T Disk buffer See Page buffer Disk contention effect of 13 17T multiple arms to reduce 10 7T Disk extent 10 8T Disk mirroring 10 5T Disk page buffer for 13 16T 13 18T size of 10 4T 13 14T Display label in ORDER BY clause 2 52T syntax in SELECT 1 3125 with SELECT 2 49T Display schema for a database 5 34R DISTINCT keyword relation to GROUP BY 3 5T restrictions in modifiable view 11 24T syntax in CREATE INDEX 1 63S in expre
323. ent For details on using descriptors see your SQL API manual The following INFORMIX ESQL C and INFORMIX ESQL COBOL examples show how to associate values from a system descriptor area exec sql put selcurs using sql descriptor descl INFORMIX ESQL C EXEC SQL PUT SEL_CURS USING SQL DESCRIPTOR DESC1 END EXEC INFORMIX ESQL COBOL PUT Using an sqlda Structure You can create an sqlda structure that describes the data type and memory location of one or more values Then you can specify the sqlda structure in the USING DESCRIPTOR clause of the PUT statement Each time the PUT statement executes the values described by the sqlda are used to replace question mark placeholders in the INSERT statement This process is similar to using a FROM clause with a list of variables except that your program has full control over the memory location of the data values For details on the sqlda structure see the INFORMIX ESQL C Programmer s Manual exec sql put selcurs using descriptor pointer2 Sample PUT USING DESCRIPTOR statement in ESQL C Writing Buffered Rows When the OPEN statement opens an insert cursor an insert buffer is created The PUT statement puts a row into this insert buffer The block of buffered rows is inserted into the database table as a block only when necessary an activity called flushing the buffer The buffer is flushed after any of the following events occur The b
324. ent must appear after the procedure header and before any other statements A variable can be used anywhere within the statement block in which it is defined that is the scope of a defined variable is the statement block in which it was defined SQL Data Type Subset 2 8 SPL Statements The SQL data type subset includes all the SQL data types except SERIAL TEXT and BYTE DEFINE Defining TEXT and BYTE Variables You can use TEXT and BYTE variables by using the REFERENCES keyword TEXT and BYTE variables do not contain the actual data but are simply point ers to the data The REFERENCES keyword is a reminder that the procedure variable is just a pointer You use the procedure variables for TEXT and BYTE data types exactly as you would any other variable Redeclaration or Redefinition If you define the same variable twice within the same statement block you receive an error A variable can be redefined within a nested block in which case it temporarily hides the outer declaration The following example produces an error CREATE PROCEDURE examplel DEFINE n INT DEFINE j INT DEFINE n CHAR 1 redefinition produces an error The redeclaration in the following example is allowed Within the nested statement block n is a character variable Outside the block n is an integer variable CREATE PROCEDURE example2 DEFINE n INT DEFINE j INT BEGIN DEFINE n CHAR 1 character n masks integ
325. ent in the same FOR EACH ROW section includ ing any cascading triggered actions If you modify a table in this section and later refer to it the changes to the table might not be complete at the time you refer to it Consequently the result might differ depending on the order in which rows are processed The database server does not enforce rules to prevent these situations because doing so would restrict the set of tables from which a triggered action can select Furthermore the result of most triggered actions is inde pendent of row order Consequently you are responsible for ensuring that the results of the triggered actions are independent of row order INSERT REFERENCING Clause 1 118 Syntax INSERT REFERENCING Clause REFERENCING NEW T T correlation name AS correlation name is a name you assign to a new column value so that you can refer to it within the triggered actions The new col umn value is the column value after the triggering state ment executes Once you assign a correlation name you can use it only inside the FOR EACH ROW triggered action See Action Clause Referencing on page 1 121 The cor relation name follows the same syntax rules as other iden tifiers See Identifier on page 1 469 The correlation name must be unique within the CREATE TRIGGER statement To use the correlation name precede the column name with the correlation name followed by a period Fo
326. ent of the value 0 73 in radians SELECT ATAN 0 73 FROM anglestbl Expression ATAN2 Function The ATAN2 function computes the angular component of the polar coordinates r 8 associated with x y The following example compares angles to 8 for the rectangular coordinates 4 5 WHERE angles gt ATAN2 4 5 determines 9 for 4 5 and compares to angles You can determine the length of the radial coordinate r using the expression shown in the following example SORT POW x 2 POW y 2 determines r for x y You can determine the length of the radial coordinate r for the rectangular coordinates 4 5 using the expression shown in the following example SORT POW 4 2 POW 5 2 determines r for 4 5 Syntax 1 461 Expression Aggregate Expressions An aggregate expression uses an aggregate function to summarize selected database data The following diagram shows aggregate function expressions p COUNT p Aa AVG column 2 AFi f name MAX DISTINCT Neria MIN p 1 506 UNIQUE SUM Synonym COUNT DISTINCT Name Wa p 1 504 UNIQUE F Name A p 1 510 Ne Expression iy AVG ae 1 ubse MAX ALL ac MIN SUM column name is the name of the column An aggregate function returns one value for a set of queried rows Some examples of aggregate functions in SELECT statements follow SELECT sum
327. ents and specify how it is to be locked J Tabl Column Name Definition We l 3 p 1 506 p Storage Constraint Option Definition p 1 105 p 1 92 TEMP temp 2 bes Column TABLE T able Sennen p 1 87 Usage 1 84 Syntax Temp Table Table Level Constraint p 1 104 z WITH NO LOG temp table name is the name that you want to assign to the temporary table You cannot use the owner convention Table names must be unique in the same database However although temporary table names must be different from existing table view or syn onym names in the current database they need not be different from other temporary table names used by other users In an ANSI compliant database the combination owner tablename must be unique within the database CREATE TABLE By default all users who have been granted the Connect privilege to a database have all access privileges except Alter Index and References to the new table To further restrict access use the REVOKE statement to take all access away from public everyone on the system Then use the GRANT statement to designate the access privileges you want to give to specific users In an ANSI compliant database no default table level privileges exist You must grant these privileges explicitly You cannot use a ROLLBACK WORK statement to undo a CREATE TABLE statement If
328. er 7 Syntax 1 37 CLOSE CLOSE Purpose Use the CLOSE statement when you no longer need to refer to the rows produced by a select or procedure cursor or when you want to flush and close an insert cursor Syntax cursor CLOSE hone cursor name is the name of a cursor that has been declared with a DECLARE statement Usage Closing a cursor makes the cursor unusable for any statements except OPEN or FREE and releases resources that the database server had allocated to the cursor A cursor that is associated with an INSERT statement is treated differ ently by a CLOSE statement than one associated with a SELECT or EXECUTE PROCEDURE statement You can close a cursor that was never opened or that has already been closed No action is taken in these cases OOE An error code is returned if you close a cursor that was not open No other action occurs Closing a Select or Procedure Cursor When cursor name is associated with a SELECT or EXECUTE PROCEDURE statement closing the cursor terminates the SELECT or EXECUTE PROCEDURE statement The database server releases all resources it may have allocated to the active set of rows for example a temporary table that it used to hold an ordered set The database server also releases any locks that it may have been 1 38 Syntax CLOSE holding on rows selected through the cursor If the CLOSE statement is contained in a transaction the locks are not released by t
329. er string for CHAR or VARCHAR integer for INTEGER and so on When any value other than DATA is set the value of DATA is undefined You cannot set the DATA field for an item without setting TYPE for that item If you set the TYPE field for an item to a character type you must also set the LENGTH field If you do not set the LENGTH field for a character item you receive an error Using LENGTH or ILENGTH If your DATA or IDATA field contains a character string you must specify a value for LENGTH If you specify LENGTH 0 LENGTH sets automatically to the maximum length of the string The DATA or IDATA field can contain a 368 Syntax 1 357 SET DESCRIPTOR E C 1 358 Syntax literal character string or a character string derived from a character variable of type CHAR or VARCHAR This provides a method to dynamically deter mine the length of a string in the DATA or IDATA field If a DESCRIBE statement precedes a SET DESCRIPTOR statement LENGTH automatically sets to the maximum length of the character field specified in your table This information is identical for ILENGTH Using DECIMAL or MONEY Types If you set the TYPE field for a DECIMAL or MONEY type and you want to use a scale or precision other than the default values set the SCALE and PRECISION fields You do not need to set the LENGTH field for a DECIMAL or MONEY item the LENGTH field is set accordingly from the SCALE and PRECISION fields Using DATETIME or INTERV
330. er variable locally END SPL Statements 2 9 DEFINE Declaring GLOBAL Variables 2 10 SPL Statements The GLOBAL modifier indicates that the list of variables that follows the keyword GLOBAL are available to other procedures The types of these vari ables must match the types of variables in the global environment The global environment is the memory used by all the procedures run within a given session a DB Access session or an SQL API session The values of global variables are stored in memory Global variables are shared between procedures running in the current session Because global variables are not saved in the database they are lost when the current session closes Global variables are not shared across databases Global procedure variables are not shared between the database server and any application development tools The first declaration of a global variable establishes the variable in the global environment subsequent global declarations simply bind the variable to the global environment establishing the value of the variable at that point The following example shows two procedures proc1 and proc2 which have both defined the global variable gl_out CREATE PROCEDURE procl DEFINE GLOBAL gl_out INT DEFAULT 13 He ET gl_out gl_out 1 D PROCEDURE ie Q REATE PROCEDURE proc2 DEFINE DEFINE DEFIN GLOBAL gl_out INT DEFAULT 23 tmp INT LET tmp
331. er_num The following example is the same as the second query in the preceding example except that it establishes table aliases in the FROM clause and uses them in the WHERE clause SELECT fname lname order_num FROM customer c orders o WHERE c customer_num o customer_num SELECT The following example uses the OUTER keyword to create an outer join and produce a list of all customers and their orders regardless of whether they have placed orders SELECT customer customer_num lname order_num FROM customer c OUTER orders o WHERE c customer_num o customer_num Creating an outer join NLS With NLS enabled the following example selects data containing foreign characters from columns in a table named with foreign characters The col lation order of the rows returned depends on environment variable settings SELECT num ro nom pr nom FROM abonn s ORDER BY nom AS Keyword with Table Aliases To use potentially ambiguous words as a table alias you must precede them with the keyword AS Use the AS keyword if you want to use the words ORDER FOR GROUP HAVING INTO UNION WHERE WITH CREATE or GRANT as a table alias WHERE Clause Use the WHERE clause to specify search criteria and join conditions on the data that you are selecting WHERE AND Clause WHERE Condition aa p 1 404 Join p 1 331 Syntax 1 325 SELECT Using a Conditio
332. ered action 1 125S qualified vs unqualified 1 126S when unqualified 1 125S Column level privilege 1 2365 11 10T COLUMNS FOR keywords in INFO statement 1 242S Command file dbload 5 23R Command script creating database 9 26T Commit two phase 12 20T COMMIT WORK statement closes cursors 7 18T releases locks 7 8T 7 18T sets SQLCODE 6 5T syntax 1 438 Committed Read isolation level 1 3675 7 10T COMMITTED READ keywords syntax in SET ISOLATION 1 3665 Comparison condition description of 2 29T syntax and use 1 405S See also Boolean expression Compiler setting environment variable for C 4 31R setting environment variable for COBOL 4 32R 4 33R specifying storage mode for COBOL 4 33R Complex relationship 8 28T Complex condition See Condition segment Complex query example of 1 364S Composite column list multiple column restrictions 1 30S 1 31S Composite index column limit 1 655 creating with CREATE INDEX 1 635 definition of 1 655 order of columns 13 31T use 13 31T Composite key 8 23T Compound assignment 2 285 Compound query 3 43T Computer network 12 4T Concatenation operator 1 4325 Concurrency Committed Read isolation 1 367S 7 10T Cursor Stability isolation 1 3675S 7 11T database lock 7 6T deadlock 7 14T defining with SET ISOLATION 1 366S description of 4 27T 7 3T Dirty Read isolation 1 367S 7 10T effect on performance 7 3T isolation level 7 9T kinds of locks 7 6T lock duration 7 8T lock scop
333. erenced in the REFERENCES clause must reside in the same database as the altered table A referential constraint establishes the relationship between columns in two tables or within the same table The relationship between the columns is com monly called a parent child relationship where for every entry in the child referencing columns there must exist a matching entry in the parent referenced columns Syntax 1 21 ALTER TABLE The referenced column parent or primary key must be a column that is a unique or primary key constraint When you specify a column in the REFERENCES clause that does not meet this criterion the database server returns an error The referencing column child or foreign key that you specify in the Add Column clause can contain null or duplicate values but every value that is all foreign key columns that contain non null values in the referencing columns must match a value in the referenced column Relationship Between Referencing and Referenced Columns A referential constraint has a one to one relationship between referencing and referenced columns In other words if the primary key is a set of col umns the foreign key also must be a set of columns that corresponds to the primary key The following example creates a new column in the cust_calls table ref_order The ref_order column is a foreign key that references the order_num column in the orders table ALTER TABLE cust_calls ADD ref_order
334. ering statement fails References See the DROP TRIGGER CREATE PROCEDURE EXECUTE PROCEDURE state ments in this manual In the Informix Guide to SQL Tutorial see Chapter 14 Syntax 1 135 CREATE VIEW CREATE VIEW Purpose Use the CREATE VIEW statement to create a new view based upon existing tables and views in the database Syntax View SELECT CREATE VIEW Name AS Statement p 1 510 ig Subset Di p t WITH CHECK column OPTION name column name is an identifier that names a column of view name The num ber of columns that you name must match the number of col umns that you select Usage Except for the statements in the following list you can use a view in any SQL statement where you can use a table ALTER INDEX DROP TABLE ALTER TABLE DROP TRIGGER CREATE INDEX LOCK TABLE CREATE TABLE RECOVER TABLE CREATE TRIGGER RENAME TABLE DROP INDEX UNLOCK TABLE The view behaves like a table with the name view name It consists of the set of rows and columns returned by the SELECT statement each time the SELECT statement is executed by using the view The view reflects changes to the underlying tables with one exception If the view is defined with a SELECT clause it has only the columns in the underlying tables at the time the view is created New columns added subsequently to the underlying tables using the ALTER TABLE statement do not appear in the view The view name
335. erostock has the same column names as the ones in the SELECT statement CREATE VIEW herostock AS SELECT stock_num description unit_price unit unit_descr FROM stock WHERE manu_code HRO If the SELECT statement returns an expression the corresponding column in the view is called a virtual column You must provide a name for virtual col umns You must also provide a column name in cases where the selected col umns have duplicate column names when the table prefixes are stripped For Syntax 1 137 CREATE VIEW example when both orders order_num and items order_num appear in the SELECT statement you must provide two separate column names to label them in the CREATE VIEW statement as shown in the following example CREATE VIEW someorders custnum ocustnum newprice AS SELECT orders order_num items order_num items total_price 1 5 FROM orders items WHERE orders order_num items order_num AND items total_price gt 100 00 If you must provide names for some of the columns in a view then you must provide names for all the columns that is the column list must contain an entry for every column appearing in the view Using a View in the SELECT Statement You can define a view in terms of other views except that you must abide by the restrictions on queries listed in Chapter 11 of the Informix Guide to SQL Tutorial WITH CHECK OPTION Keywords The WITH CHECK OPTION keywords instruct the database s
336. erver to start recording transactions to make a database ANSI compliant to change the name of an existing transaction log file or to remove logging on a data base Database EA START DATABASE Name WITH LOG IN pathname p 1 421 ac S MODE ANSI Usage 1 376 Syntax WITH NO LOG pathname is the pathname of the transaction log file enclosed in quotation marks The directory mentioned in the pathname must exist To use the START DATABASE statement all of the following conditions must be true e You have the DBA privilege e No current database exists The directories specified in pathname exist For maximum protection specify a location for the transaction log that is not on the same storage device as the database Issue a CLOSE DATABASE statement before you create and start a transaction log The START DATABASE statement locks the database exclusively to pre vent access by other processes If another process is using the database even if the database is only being read the START DATABASE statement fails The database remains locked after the START DATABASE statement executes When you are satisfied that the database is ready to use remove the exclusive lock by executing the CLOSE DATABASE statement Reopen the database with the DATABASE statement START DATABASE MODE ANSI Keyword Use the MODE ANSI keyword to make a database ANSI compliant An ANSI compliant database conforms to d
337. erver to ensure that all modifications made through the view to the underlying tables satisfy the definition of the view The following example creates a view named palo_alto that uses all the information in the customer table for customers in the city of Palo Alto The database server checks any modifications made to customer through palo_alto because the WITH CHECK OPTION is specified CREATE VIEW palo_alto AS SELECT FROM customer WHERE city Palo Alto WITH CHECK OPTION 1 138 Syntax CREATE VIEW Updating through Views If a view is built ona single table the view is said to be updatable if the SELECT statement that defined it did not contain any of the following items Columns in the select list that are aggregate values Columns in the select list that use the UNIQUE or DISTINCT keyword A GROUP BY clause e A derived value for a column created using an arithmetical expression That means in an updatable view the values in the underlying table can be updated by inserting values into the view Note You cannot update or insert rows to a remote table through views with check options References See the CREATE TABLE DROP VIEW GRANT and SELECT statements in this manual In the Informix Guide to SQL Tutorial see the discussions of views and security in Chapter 11 Syntax 1 139 DATABASE DATABASE Purpose Syntax Usage 1 140 Syntax Use the DATABASE statement to sel
338. ery 1 330S 3 33T DISCONNECT statement 1 169S syntax in expression 1 462S in GRANT 1 235S in REVOKE 1 301S in SELECT 1 312S with UNION operator 1 310S use in Condition subquery 1 415S in expression 1 463S in GRANT 1 236S in SELECT 1 313S with UNION operator 1 344S ALLOCATE DESCRIPTOR statement syntax 1 95 with concatenation operator 1 432S Allocating memory with the ALLOCATE DESCRIPTOR statement 1 95 ALTER INDEX statement creating clustered index 1 125 10 25T dropping clustered index 1 135 locks table 7 7T syntax 1 128 See also Index Name segment ALTER keyword syntax in GRANT 1 231S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S Alter privilege 1 2365S 11 8T ALTER TABLE statement ADD clause 1 17S ADD CONSTRAINT clause 1 30S adding a column 1 175 adding a column constraint 1 295 and NCHAR column 1 19R and NVARCHAR column 1 19R cascading deletes 1 225 changing column data type 1 275 9 19T changing table lock mode 1 33S CHECK clause 1 25S DEFAULT clause 1 188 DROP clause 1 26S DROP CONSTRAINT clause 1 32S dropping a column 1 265 dropping a column constraint 1 32S LOCK MODE clause 1 33S MODIFY NEXT SIZE clause 2 9R 1 33S NEXT SIZE clause 10 8T ON DELETE CASCADE keyword 1 21S PAGE keyword 1 335 privilege for 1 231S 11 10T reclustering a table 1 135 REFERENCES clause 1 215 ROW keyword 1 33S rules for primary key constraints rules for unique constraints 1 315 American National Standards Institute
339. es the existing audit trail on the orders table DROP AUDIT FOR orders References See the CREATE AUDIT and RECOVER TABLE statements in this manual In the INFORMIX SE Administrator s Guide see the discussion on audit trails in Chapter 2 Syntax 1 171 DROP DATABASE DROP DATABASE Purpose Syntax Usage 1 172 Syntax Use the DROP DATABASE statement to delete an entire database including all system catalog tables indexes and data Database Name p 1 421 DROP DATABASE You must have the DBA privilege or be user informix to run the DROP DATABASE statement successfully Otherwise the database server issues an error message and does not drop the database You cannot drop the current database or a database that is being used by another user All the database users must first execute the CLOSE DATABASE statement The DROP DATABASE statement cannot appear in a multistatement PREPARE statement The following statement drops the stores6 database DROP DATABASE stores6 The user informix must have write permission to the database directory that is to be dropped When you drop a database with transactions the transaction log file associated with the database is removed Use this statement with caution DB Access does not prompt you to verify that you want to delete the entire database DROP DATABASE sy You can use a simple database name in a program or host variable or
340. ess is limited by the amount of free memory available in the system Use FREE statement id or FREE statement id variable to release the resources held by a prepared statement use FREE cursor id or FREE cursor variable to release resources held by a cursor Syntax 1 207 FREE Freeing a Statement If you prepared a statement but did not declare a cursor for it FREE statement id or statement id variable releases the resources in both the application development tool and the database server If you declared a cursor for a prepared statement FREE statement id or statement id variable releases only the resources in the application develop ment tool the cursor can still be used The resources in the database server are released only when you free the cursor After freeing a statement you cannot execute it or declare a cursor for it until you prepare it again The following INFORMIX ESQL C example shows the sequence of statements used to free an implicitly prepared statement exec sql prepare sel_stmt from select from orders exec sql free sel_stmt The following INFORMIX ESQL C example shows the sequence of statements used to release the resources of an explicitly prepared statement sprintf demoselect Ss s select from customer where customer_num between 100 and 200 exec sql prepare sel_stmt from demoselect exec sql declare sel_curs cursor for sel_stmt exec sql open sel_curs exec sql
341. est DIRTY READ COMMITTED READ CURSOR STABILITY REPEATABLE READ Provides zero isolation Dirty Read is appropriate for static tables that are used for queries With a Dirty Read isolation level a query may return a phantom row that is an uncommitted row that was inserted or modified within a transaction that has subsequently rolled back No other isolation level allows access to a phantom row Dirty Read is the only isolation level available to databases that do not have transactions Guarantees that every row retrieved is committed in the table at the time that the row is retrieved Even so no locks are acquired While one process uses a row another process can acquire an exclusive lock on the same row and modify or delete data in the row Com mitted Read is the default level of isolation in a database with logging that is not ANSI compliant Acquires a shared lock on the selected row Another process also can acquire a shared lock on the same row but no process can acquire an exclusive lock to modify data in the row When you fetch another row or close the cursor INFORMIX OnLine Dynamic Server releases the shared lock Acquires a shared lock on every row selected during the transaction Another process can also acquire a shared lock on a selected row but no other process can modify any selected row during your transaction If you repeat the query during the transaction you reread the same information The shared locks
342. estimated cost the output file also contains the following information e An estimate of the number of rows to be returned e The order in which tables are accessed during execution The table column or columns that serve as a filter if any and whether the filtering is through an index The method access path by which the executor reads each table which is one of the methods in the following list SEQUENTIAL SCAN reads rows in sequence INDEX PATH scans one or more indexes AUTOINDEX PATH creates a temporary index SORT SCAN sorts the result of the preceding join or table scan MERGE JOIN uses a sort merge join instead of nested loop join REMOTE PATH accesses another distributed database The optimizer chooses the best path of execution to produce the fastest possible table join using a nested loop join or sort merge join wherever appropriate The SORT SCAN section indicates that sorting the result of the preceding join or table scan is to be done in preparation for a sort merge join It includes a list of the columns that form the sort key The order of the columns is the Syntax 1 361 SET EXPLAIN 1 362 Syntax order of the sort As with indexes the default order is ascending Where pos sible this ordering is arranged to support any requested ORDER BY or GROUP BY clause If the ordering can be generated from a previous sort or an index lookup the SORT SCAN section does not appear The MERGE JOIN section i
343. etch only the next row in sequence from the active set The sole keyword option available to a sequential cursor is the default value NEXT A sequential cursor can read through a table only once each time it is opened The following example in INFORMIX ESOQL C illustrates the use of a sequential cursor exec sql fetch seq_curs into fname lname Syntax 1 195 FETCH When the program opens a sequential cursor the database server processes the query to the point of locating or constructing the first row of data The goal of the database server is to tie up as few resources as possible Because the sequential cursor can retrieve only the next row it is frequently possible for the database server to create the active set one row at a time On each FETCH operation the database server returns the contents of the current row and locates the next row This one row at a time strategy is not possible if the database server must create the entire active set to determine which row is the first row as would be the case if the SELECT statement included an ORDER BY clause FETCH with a Scroll Cursor A scroll cursor can fetch any row in the active set either by specifying an absolute row position or a relative offset You use keywords found in the following list to specify a particular row that you want to retrieve NEXT retrieves the next row in the active set PREVIOUS retrieves the previous row in the active set PRIOR is synonymous
344. eywords on temporary tables created in temporary dbspaces Using the WITH NO LOG keywords prevents logging of temporary tables in databases started with logging If you use the WITH NO LOG keywords in a CREATE TABLE statement and the database does not use logging the WITH NO LOG option is ignored Once you turn off the logging on a temporary table you cannot turn it back on a temporary table is therefore always logged or never logged CREATE TABLE The following example shows how to prevent logging of temporary tables in a database that uses logging CREATE TEMP TABLE tab2 fname CHAR 15 lname CHAR 15 WITH NO LOG Storage Option Storage Option Extent Option TAT LOCK MODE P IN ebspace p 1 107 p 1 108 SE IN pathname dbspace is the name of the dbspace in which the database table is to be stored pathname specifies the full operating system path and filename in which you want to store the database table with no extension to the filename The storage option allows you to specify where the database table is stored and the locking granularity for the table The IN dbspace Clause The IN dbspace clause allows you to isolate a table The dbspace that you specify must already exist If you do not specify the IN dbspace clause the default is the dbspace in which the current database resides Syntax 1 105 CREATE TABLE 1 106 Syntax For example if the sto
345. f GET DIAGNOSTICS GET DIAGNOSTICS fields into host variables The contents of the host variables are displayed by printf statements in lines 100 101 and 108 through 112 1 include lt stdio h gt 2 3 Uncomment the following line if the database has 4 transactions J EXEC SQL define TRANS 6 7 EXEC SQL define FNAME_LEN 15 8 EXEC SQL define LNAME_LEN 15 9 0 EXEC SQL BEGIN DECLARE SECTION 1 char SQLSTATE 6 2 EXEC SQL END DECLARE SECTION 3 4 char statement 20 5 6 main 7 8 EXEC SQL BEGIN DECLARE SECTION 9 char fname FNAME_LEN 1 20 char lname LNAME_LEN 1 2I EXEC SQL END DECLARE SECTION 22 23 24 printf DEMO1 Sample ESQL program running n n 25 26 EXEC SQL WHENEVER SQLERROR CALL sql_err 27 EXEC SQL WHENEVER SQLWARNING CALL sql_err 28 29 strcpy statement CONNECT stmt 30 EXEC SQL connect to stores6 31 32 strcpy statement DECLARE stmt 33 EXEC SQL declare democursor cursor for 34 select fname lname 35 into fname lname 36 from customer 37 where lname gt C 38 39 EXEC SQL ifdef TRANS 40 strcpy statement BEGIN WORK stmt 41 EXEC SQL begin work 42 EXEC SQL endif 43 44 strcpy statement OPEN stmt 45 EXEC SQL open democursor 46 47 strcpy statement FETCH stmt 48 for 49 50 EXEC SQL fetch democursor 51 if sql_err 2 52 break De printf Ss Ss n fname lname 54 55 56 strcpy statement CLOSE stmt Sr EXEC S
346. f you omit the WHERE clause while working within the SQL menu DB Access prompts you to verify that you want to delete all rows from a table You do not receive a prompt if you run the DELETE statement within a command file Statements are always within an implicit transaction in an ANSI compliant database therefore you cannot have a DELETE statement outside a transac tion Using Cascading Deletes Use the ON DELETE CASCADE option of the REFERENCES clause on either the CREATE TABLE or ALTER TABLE statement to specify that you want deletes to cascade from one table to another For example the stock table contains the column stock_num as a primary key The catalog and items tables each con tain the column stock_num as foreign keys with the ON DELETE CASCADE option specified When a delete is performed from the stock table rows are also deleted in the catalog and items tables which are referred through the foreign keys If a cascading delete is performed without a WHERE clause all rows in the parent table and subsequently the affected child tables are deleted WHERE Clause 1 160 Syntax Use the WHERE clause to specify one or more rows that you want to delete The WHERE conditions are the same as the conditions in the SELECT state ment For example the following statement deletes all the rows of the items table where the order number is less than 1034 DELETE FROM items WHERE order_num lt 1034 If you include a WHER
347. field For the TYPE field the correspondence between the integer codes and data types is provided in Figure 1 11 on page 1 356 is an unsigned integer that represents one of the items in the system descriptor area is the name of an integer host variable that contains an unsigned integer that represents one of the items in the system descriptor area is a positive nonzero integer that represents the data type of the item The correspondence between the integer codes and data types is provided in Figure 1 11 on page 1 356 is a literal integer that specifies how many items are being described in the system descriptor area The value must be less than or equal to the number of occurrences in the sys tem descriptor area which is set when the area is allocated Use the SET DESCRIPTOR statement to assign values to a system descriptor area in the following instances To set the COUNT field of a system descriptor area to match the number of items for which you are providing descriptions in the system descriptor area Typically the items are in a WHERE clause e To set the item descriptor fields for each value for which you are providing descriptions in the system descriptor area Typically the items are in a WHERE clause e To modify the contents of an item descriptor field after you use the DESCRIBE statement to fill the fields for a SELECT or an INSERT statement SET DESCRIPTOR If an error occurs during the assignment to
348. fig file specifying with ONCONFIG 4 40R One to many relationship 8 9T 8 11T One to one relationship 8 9T 8 11T OnLine 5 10T On line files Intro 8R Intro 11S 6T help Intro 9R Intro 11S 7T onload utility 4 27T 10 11T onstat utility 10 12T onunload utility 4 27T 10 11T OPEN statement activating a cursor 5 20T constructing the active set 1 264S opening a procedure cursor 1 265S opening an insert cursor 1 266S opening select or update cursors 1 2645 5 20T reopening a cursor 1 2675 substituting values for parameters 1 268S syntax 1 263S with concatenation operator 1 432S with FREE 1 269S Opening a cursor 5 20T 5 24T Operating system DOS 12 4T UNIX 12 4T Optical device 12 6T Optimization specifying a high or low level 1 374S Optimizer and GROUP BY 13 10T 13 12T 13 27T and ORDER BY 13 10T 13 12T 13 27T and SET OPTIMIZATION statement 1 3745 13 36T autoindex path 13 29T composite index use 13 31T data distributions 13 29T disk access 13 14T display query plan 13 12T filter selectivity 13 30T index not used by 13 32T 13 35T index used by 13 9T 13 10T methods of 13 8T query plan 13 22T sort merge join 13 27T sorting 13 12T specifying high or low level of optimization 13 36T system catalog use 13 9T when index not used 13 33T with UPDATE STATISTICS 1 3945 Optimizing a query 1 360S a server 1 3745 across a network 1 374S techniques 13 3T Optional entity in relationship 8 9T OR keyword syntax in Condi
349. file containing the Documentation Notes for this product is called SQLRDOC 6 0 Release Notes describe feature differences from earlier versions of Informix products and how these differences may affect current prod ucts The file containing the Release Notes for Version 6 0 of Informix database server products is called SERVERS_6 0 Machine Notes describe any special actions required to configure and use Informix products on your machine Machine notes are named for the product described for example the machine notes file for INFORMIX OnLine Dynamic Server is ONLINE_6 0 Please examine these files because they contain vital information about application and performance issues A number of Informix products also provide on line Help files that walk you through each menu option To invoke the Help feature simply press CTRL W wherever you are in your Informix product ASCII and PostScript Error Message Files Informix software products provide ASCII files that contain all the Informix error messages and their corrective actions To access the error messages in the ASCII file Informix provides scripts that let you display error messages on the screen finderr or print formatted error messages rofferr See the Introduction to the Informix Error Messages manual for a detailed description of these scripts The optional Informix Messages and Corrections product provides Post Script files that contain the error messages and their correct
350. five character string that can contain only the following elements e Digits Capital letters Syntax 1 217 GET DIAGNOSTICS The first two characters of the SQLSTATE code indicate a class The last three characters of the SQLSTATE code indicate a subclass Figure 1 6 shows the structure of the SOLSTATE code WV CLASS SUBCLASS CODE CODE Figure 1 6 The structure of the SQLSTATE code using the value 08001 where 08 is the class code and 001 is the subclass code The value 08001 represents the error unable to connect with database environment The class code of SQLSTATE is unique but the subclass code is not The meaning of the subclass code depends on the accompanying class code The initial character of the class code indicates the source of the SOLSTATE value as described in the following list e Class codes that begin with a digit in the range 0 4 or a capital letter in the range A H indicate that the result code is defined by ANSI ISO In this case the associated subclass codes also begin in the range 0 4 or A H Class codes that begin with the letters IX indicate error or warning conditions used only by Informix Informix uses codes starting with IX to support any existing warning or error messages that are not supported by ANSI ISO Other class codes that begin with a digit in the range 5 9 or a capital letter in the range I Z other than IX indicate conditions that are currently
351. for Null Values You can modify an existing column that formerly permitted nulls to disallow nulls provided that the column does not contain null values To do this spec ify MODIFY with the same column name and data type and the NOT NULL keywords You can modify an existing column that did not permit nulls to permit nulls To do this specify MODIFY with the column name and the existing data type and omit NOT NULL However if a unique index exists on the column you may remove it using the DROP INDEX statement ADD CONSTRAINT Clause ADD CONSTRAINT Clause Constraint p gt ADD CONSTRAINT Definition p J Constraint Definition Constraint Definition Toa ne aaa ie UNIQUE colum 4 DISTINCT n EMORY CONSTRAINT COnstraint REFERENCES p 1 419 N_ FOREIGN column _ Clause LJ ss CHECK J Clause p 1 25 column is the name of the column or columns on which the constraint is placed Syntax 1 29 ALTER TABLE Use the ALTER TABLE statement with the ADD CONSTRAINT keywords to specify a constraint on a new or existing column or on a set of columns For example to add a unique constraint to the fname and Iname columns of the customer table use the following example ALTER TABLE customer ADD CONSTRAINT UNIQUE lname fname To name the constraint change the preceding example as shown in the fol lowing example
352. for each group A group is a set of rows that have the same values for each column listed 1 334 Syntax GROUP BY column Ba Clause C gt GROUP BY N U Table Name p 1 506 View N Name L A p 1 510 Synonym N Name LA p 1 504 No alias _ 7 H select number column name is the name of a column or set of columns joined by a Ea name y relational operator that is in the SELECT clause Do not include BYTE or TEXT columns select number is an integer that represents the placement of a column or expression in the SELECT clause alias is aname you attach to a table or view within the scope of the SELECT statement Using a GROUP BY clause restricts what you can enter in the SELECT clause If you use a GROUP BY clause each of the columns that you select must be in the GROUP BY list If you use an aggregate function and one or more column expressions in the select list you must put all the column names that are not used as part of an aggregate or time expression in the GROUP BY clause Do not put constant expressions or BYTE or TEXT column expressions in the GROUP BY list If you are selecting a BYTE or TEXT column you cannot use the GROUP BY clause In addition you cannot use ROWID in a GROUP BY clause SELECT The following example names one column that is not in an aggregate expression The total_price column should not be in the GROUP BY list
353. from reading or modifying the contents of the row until the lock is released INFORMIX OnLine Dynamic Server allows only one update lock at a time on a row or a page the type of lock depends on the lock mode selected in the CREATE TABLE or ALTER TABLE statements An update process can acquire an update lock on a row or a page that has a shared lock from another pro cess but you cannot promote the update lock from shared to exclusive and the update cannot occur until the other process releases its lock If the number of rows affected by a single update is very large you can exceed the limits placed on the maximum number of simultaneous locks If this occurs you can reduce the number of transactions per UPDATE state ment or lock the page INFORMIX OnLine Dynamic Server database servers only or the entire table before you execute the statement Individual rows of a table are locked automatically when you execute an UPDATE statement Syntax 1 385 UPDATE SET Clause SET Clause G column ir es name Expression Subset p 1 386 SELECT Statement Subset V p 1 386 NULL 3 Caan name Bi 2 Subset p 1 38 Expression SELECT Statement Subset p 1 386 NULL y indicates that you want to update all columns in table name view name or synonym name column name names the columns that you want to update You c
354. g a column with 1 285 rules of use 1 305 1 925 1 94S UNIQUE keyword constraint in CREATE TABLE 9 24T restrictions in modifiable view 11 24T syntax in CREATE INDEX 1 635 in CREATE TABLE 1 915 in SELECT 1 3125 use in ALTER TABLE 1 295 in CREATE INDEX 1 645 in CREATE TABLE 1 925 in expression 1 462S in SELECT 1 3138 2 19T no effect in subquery 1 414S UNITS keyword syntax in expression 1 436S use in expression 1 4425 UNIX BSD default print capability 4 7R 4 24R viewing environment settings 4 5R environment variables listed 4 9R PATH environment variable 4 54R specifying directories for intermediate writes 4 40R System V default print capability 4 7R 4 24R terminfo library support 4 39R viewing environment settings 4 5R TERM environment variable 4 55R TERMCAP environment variable 4 56R TERMINFO environment variable 4 56R UNIX operating system 12 4T 12 6T UNLOAD statement DELIMITER clause 1 380S exporting data to a file 9 27T specifying field delimiter with DBDELIMITER 4 18R syntax 1 378S UNLOAD TO file 1 378S unloading VARCHAR TEXT or BYTE columns 1 379S NLOAD TO file 1 378S nloading a database 5 8R NLOCK TABLE statement syntax and use 1 381S nnamed pipes 12 7T pdatable view 1 139S PDATE clause syntax 1 114S pdate cursor 1 1485 definition of 1 148S 6 15T locking considerations 1 152S opening 1 264S restricted statements 1 152S use in UPDATE 1 390S using 1 152S Update journal 10 33T UPDATE keyword syntax
355. g with ALTER TABLE 1 285 CHAR 3 6R 9 15T CHARACTER 3 7R character data 9 15T CHAR mapping to NCHAR 4 46R choosing 9 19T chronological 9 12T considerations for INSERT 1 2515S 1 498S conversion 3 23R 4 8T DATE 3 7R 9 12T DATETIME 3 7R 9 12T DEC 3 10R DECIMAL 3 10R 9 10T DOUBLE PRECISION 3 12R fixed point 9 10T FLOAT 3 12R floating point 3 12R 9 9T in SPL variables 14 17T INT 3 13R INTEGER 3 13R 9 7T INTERVAL 3 13R 9 14T MONEY 3 16R 9 10T NCHAR 3 17R NCHAR mapping to CHAR 4 46R NUMERIC 3 18R numeric 9 7T NVARCHAR 3 18R REAL 3 19R 9 9T requirements for referential constraints 1 22S 1 96S segment 1 4245 SERIAL 3 19R 9 7T SMALLFLOAT 3 20R 9 9T SMALLINT 3 20R specifying with CREATE VIEW 1 137S summary table 3 4R syntax 1 425S TEXT 3 21R 9 17T VARCHAR 3 22R 9 15T See also Data Type segment Data types creating NCHAR columns 1 19R creating NVARCHAR columns 1 19R OnLine specific 1 4R Database ANSI compliant 1 15T application 1 16T archiving 1 10T closing with CLOSE DATABASE 1 415 concurrent use 1 8T creating ANSI compliant 1 376S creating in NLS mode 1 20R creating with CREATE DATABASE 1 575 data types 3 4R default isolation levels 1 368S defined 1 3T 1 11T dropping 1 172S implicit connection 1 168S lock 1 1425 management of 1 9T map of stores6 A 6R system catalog tables 2 33R mission critical 1 10T naming conventions 1 4225 Index 11 naming unique to engine 9 21T naming with variable 1 42
356. ge locking allows you to obtain and release one lock on a whole page of rows Page locking is especially useful when you know that the rows are grouped into pages in the same order that you are using to process all the rows For example if you are processing the contents of a table in the same order as its cluster index page locking is especially appropriate You can change the lock mode of an existing table with the ALTER TABLE statement CREATE TABLE The IN pathname Option The pathname in an IN clause can specify any valid directory and is not restricted to the directory that contains the current database This allows you to spread your tables over multiple disks In UNIX the pathname cannot be longer than 64 characters and must be within quotes A pathname must be in the following form directory name filename If the pathname in an IN clause specifies a filename that is different from the table name always use the table name rather than the filename to refer to the table in subsequent SQL statements The creator of the table must have search permissions on all directories in the path and write permissions on the directory that is to contain the files References See the ALTER TABLE CREATE INDEX CREATE DATABASE and DROP TABLE statements in this manual Also see the Data Type segment on page 1 424 In the Informix Guide to SQL Tutorial see the discussions of data integrity in Chapter 3 creating a table in
357. generated number in SQLERRD 5 12T in ALTER TABLE 1 175 in INSERT 1 2515 inserting a starting value 4 8T inserting values 3 19R resetting values 3 19R syntax 1 425S treatment by dbschema 5 34R with stored procedures 2 85 Server See Database server SET clause 1 125S 4 14T SET CONNECTION statement syntax and use 1 346S with concatenation operator 1 432S SET CONSTRAINTS statement syntax and use 1 349S use with CREATE TRIGGER 1 131S SET DEBUG FILE TO statement syntax and use 1 351S with TRACE 2 425 SET DESCRIPTOR statement syntax 1 353S the VALUE option 1 355S with concatenation operator 1 4325 X Open mode 1 3575 Set difference 3 53T SET EXPLAIN statement interpreting output 1 361S 13 29T MERGE JOIN information 1 362S optimizer access paths 1 361S output examples 1 362S SORT SCAN information 1 3625 syntax 1 360S writes query plan 13 12T Set intersection 3 51T SET ISOLATION statement controlling the effect of locks 4 28T default database levels 1 368S definition of isolation levels 1 367S effects of isolation 1 368S restrictions 7 9T syntax 1 366S SET keyword syntax in UPDATE 1 383S use in UPDATE 1 386S 4 12T Index 39 SET LOCK MODE statement controlling the effect of locks 4 28T description of 7 13T kernel locking 1 370S setting wait period 1 371S syntax 1 370S SET LOG statement buffered vs unbuffered 1 372S 9 22T syntax 1 372S SET OPTIMIZATION statement syntax and use 1 374S Setting environment variables 4
358. ggering statement is shown in the following example UPDATE taba SET b c b 1 c 1 Then trig1 for columns a and c executes first and trig2 for columns b and d executes next In this case the smallest column number in the two triggers is column 1 a and the next is column 2 b Syntax 1 115 CREATE TRIGGER Action Clause Action Clause a BEFORE ROW Triggered _ FOR EACH nggere j Triggered Action List ra p 1 121 iT REACH _ Triggered ran Triggered i S OR EACH _ AFTER Action List Action List ROW p 1 121 p 1 121 Action List p 1 121 ae AFTER Triggered Action List p 1 121 Triggered _____ aFTER Acton List 4 p 1 121 The action clause specifies when the triggered actions occur and defines what they are You must define at least one triggered action using the keywords BEFORE FOR EACH ROW or AFTER to indicate when the action occurs rela tive to the triggering statement You can define triggered actions for all three options on a single trigger but you must order them in sequence BEFORE FOR EACH ROW and then AFTER You cannot follow a FOR EACH ROW trig gered action list with a BEFORE triggered action list If the first triggered action list is FOR EACH ROW an AFTER action list is the only option that can follow it See Action Clause Referencing on page 1 121 for more information on th
359. ginning of the loop Subsequently the condition is evaluated at the beginning of each iteration The statement block is executed as long as the condition remains true The loop terminates when the condition evaluates to not true If any expression contained within the condition evaluates to NULL the condition automatically becomes not true unless you are explicitly testing for the IS NULL condition If an expression within the condition has an UNKNOWN value because it references uninitialized procedure variables it is an immediate error In this case the loop terminates and an exception is raised CREATE PROCEDURE simp_while EFINE i INT EFINE pf_name CHAR 15 WHILE EXISTS SELECT fname INTO pf_name FROM customer WHERE customer_num gt 400 DELETE FROM customer WHERE id_2 2 END WHILE SEs LET i 1 WHILE i lt 10 INSERT INTO tab_2 VALUES i LET i i 1 END WHILE END PROCEDURE Index This index covers the Tutorial Reference and Syntax manuals Page numbers that end in T can be found in the Tutorial those that end in R can be found in the Reference Manual and those that end in S can be found in the Syntax manual Special symbols are listed in ASCII order at the end of the index A ABS function syntax in expression 1 4445 use in expression 1 445S ABSOLUTE keyword syntax in FETCH 1 1945 use in FETCH 1 196S Access control See Privilege ACCESS FOR keywords in
360. gl_out END PROCEDURE If proc is called first gl_out is set to 13 and then incremented to 14 If proc2 is then called it sees that the value of gl_out is already defined so the default value of 23 is not applied Then proc2 assigns the existing value of 14 to tmp If proc2 had been called first gl_out would have been set to 23 and 23 would have been assigned to tmp Later calls to procl would not apply the default of 13 Providing Default Values You can provide a literal value or a null value as the default for a global variable You also can use a call to an SQL function to provide the default value The following example uses the SITENAME function to provide a default value It also defines a global BYTE variable CREATE PROCEDURE gl_def DEFINE GLOBAL gl_site CHAR 18 DEFAULT SITENAME DEFINE GLOBAL gl_byte REFERENCES BYTE DEFAULT NULL i 53 END PROCEDURE SITENAME or DBSERVERNAME If you use the value returned by SITENAME or DBSERVERNAME as the default the variable must be a CHAR VARCHAR NCHAR or NVARCHAR value of at least 18 characters USER If you use USER as the default the variable must be a CHAR VARCHAR NCHAR or NVARCHAR value of at least eight characters SPL Statements 2 11 DEFINE CURRENT If you use CURRENT as the default the variable must be a DATETIME value If your variable has been qualified with the YEAR TO FRACTION keyword you can use CURRENT
361. gt ALL SELECT total_price FROM items WHERE order_num 1023 SELECT DISTINCT order_num FROM items WHERE total_price gt SELECT MAX total_price FROM items WHERE order_num 1023 SELECT The following SELECT statements return the order number of all orders that contain an item whose total price is greater than the total price of at least one of the items in order number 1023 The first statement uses the ANY keyword the second uses the MIN aggregate function SELECT DISTINCT order_num FROM items WHERE total_price gt ANY SELECT total_price FROM items WHERE order_num 1023 SELECT DISTINCT order_num FROM items WHERE total_price gt SELECT MIN total_price FROM items WHERE order_num 1023 You can omit the keywords ANY ALL or SOME in a subquery if you know that the subquery returns exactly one value If you omit ANY ALL or SOME and the subquery returns more than one value you receive an error The sub query in the following example returns only one row because it uses an aggregate function SELECT order_num FROM items WHERE stock_num 9 AND quantity SELECT MAX quantity FROM items WHERE stock_num 9 Using a Join in the WHERE Clause You join two tables when you create a relationship in the WHERE clause between at least one column from one table and at least one column from another table The effect of the join is to create a temporary comp
362. guments to the procedure and the proce dure must be declared to accept values If the statement was previously pre pared the statement passed to the database server when it was prepared The database server executes the procedure to the point of the first set of values returned by the procedure Because this is the first time that the database server sees the procedure it is the time when many errors are detected The database server does not actu ally return the first row of data but it sets a return code in the SQLCODE field of the sqlca The name of the field in each product is indicated in the following table Product Field Name ESQL C sqlca sqlcode SQLCODE ESQL COBOL SQLCODE OF SQLCA Syntax 1 265 OPEN The return code value is either negative or zero as described in the following list negative An error was detected in the EXECUTE PROCEDURE statement zero The EXECUTE PROCEDURE statement is valid If the EXECUTE PROCEDURE statement is valid but no rows are returned the first FETCH statement returns a value of 100 SQLNOTFOUND which means no rows found The procedure must be created to return values that is the procedure must have a RETURNING clause at the beginning of the procedure Note When you encounter an SQLCODE error be aware that there may be a corresponding SQLSTATE error value Check the GET DIAGNOSTICS statement for information about how to get the SQLSTATE value and how to use the GET DIAGNO
363. h GRANT 1 788 CREATE SYNONYM statement ANSI compliant naming 1 80S chaining synonyms 1 83S synonym for a table 1 80S synonym for a view 1 80S syntax 1 80S use of dbschema 5 34R with CREATE SCHEMA 1 77S CREATE TABLE use of dbschema 5 34R CREATE TABLE statement and COLLCHAR environment variable 4 46R and NCHAR column 1 19R and NVARCHAR column 1 19R cascading deletes 1 975 CHECK clause 1 985 creating temporary table 1 100S DEFAULT clause 1 885 defining constraints at column level 1 915 at table level 1 925 description of 9 24T EXTENT SIZE clause 10 8T in command script 9 26T IN dbspace clause 1 105S locating BLOB column 10 18T LOCK MODE clause 1 108S naming conventions 1 845 NEXT SIZE clause 10 8T ON DELETE CASCADE keyword 1 945 REFERENCES clause 1 945 rules for primary keys 1 94S rules for referential constraints 1 945 rules for unique constraints 1 94S sets initial SERIAL value 9 8T setting columns NOT NULL 1 205 1 905 specifying extent size 1 107S specifying table columns 1 875 storing database tables 1 105S syntax 1 845 with BLOB data types 1 915 with CREATE SCHEMA 1 77S CREATE TRIGGER statement in ESQL C 1 111S in ESQL COBOL 1 111S privilege to use 1 111S purpose 1 110S syntax 1 110S triggered action clause 1 121S use 1 1115 CREATE VIEW statement Index 9 column data types 1 137S privileges 1 137S restrictions on 11 22T syntax 1 136S use of dbschema 5 34R using 11 20T virtual column 1 137S WITH
364. hat attempt to access the same rows simultaneously SET ISOLATION TO DIRTY READ COMMITTED READ CURSOR STABILITY REPEATABLE READ The database isolation level affects read concurrency when rows are retrieved from the database INFORMIX OnLine Dynamic Server uses shared locks to support four levels of isolation among processes attempting to access data The update or delete process always acquires an exclusive lock on the row being modified The level of isolation does not interfere with rows that you are updating or deleting If another process attempts to update or delete rows that you are reading with an isolation level of Repeatable Read that process will be denied access to those rows Cursors that are currently open when you execute the SET ISOLATION statement may or may not use the new isolation level when rows are later retrieved The isolation level in effect could be any level that was set from the time the cursor was opened until the time the application actually fetches a row This happens because the database server may have read rows into internal buffers and internal temporary tables using the isolation level that was in effect at that time To ensure consistency and reproduce able results close open cursors before executing the SET ISOLATION statement Isolation Levels SET ISOLATION The following definitions explain the critical characteristics of each isolation level from the lowest level of isolation to the high
365. he NULL keyword to modify a column value when using the UPDATE statement For a customer whose previous address required two address lines but now requires only one you would use the following entry exec sql update customer set addressl 123 New Street set address2 null city Palo Alto zipcode 94303 where customer_num 134 Multiple Columns Equal to Multiple Expressions The SET clause offers the following options for listing a series of columns you intend to update e Explicitly list each column separating by commas and enclosing all in parentheses Implicitly list all columns in table name using the asterisk notation Syntax 1 387 UPDATE To complete the SET clause you must list each expression explicitly separated by commas and all enclosed in parentheses An expression list can include an SQL subquery that returns a single row of multiple values as long as the number of columns named explicitly or implicitly equals the number of values produced by the expression or expressions that follow the equal sign The following examples illustrate the multiple column to multiple expression form of the SET clause UPDATE customer SET fname lname John Doe WHERE customer_num 101 UPDATE manufact SET HNT Hunter WHERE manu_code ANZ UPDATE items SET stock_num manu_code quantity SELECT stock_num manu_code FROM stock WHERE description baseball 2
366. he current database The database name you use must be unique within the INFORMIX OnLine Dynamic Server environment in which you are working OnLine creates the system catalog tables containing the data dictionary that describes the struc ture of the database in the dbspace If you do not specify the dbspace OnLine creates the system catalog tables in the root dbspace Syntax 1 57 CREATE DATABASE 1 58 Syntax When you create a database you alone have access to it The database remains inaccessible to other users until you as database administrator DBA grant database privileges For information on granting database privileges see GRANT on page 1 231 The following statement creates the vehicles database in the root dbspace CREATE DATABASE vehicles The following statement creates the stores6 database in the research dbspace CREATE DATABASE vehicles IN research The following example creates the stores6 database in your current directory CREATE DATABASE vehicles The data for the database is placed in a subdirectory of your current directory with the name database name dbs The system catalog tables data and index files are placed in this directory except for tables that you explic itly instruct be placed elsewhere see the CREATE TABLE statement on page 1 84 The rules for directory names on your operating system govern the length of the name that you choose for the
367. he database server until you execute COMMIT WORK or ROLLBACK WORK After you close a select or procedure cursor you cannot execute a FETCH statement that names it until you have reopened the cursor Closing an Insert Cursor When cursor name is associated with an INSERT statement the CLOSE statement writes any remaining buffered rows into the database The number of rows that were successfully inserted into the database is returned in the third element of the sqlerrd array in the sqlca structure the product specific name of which is shown in the following chart For information on using SQLERRD to count the total number of rows inserted see the PUT statement on page 1 284 Product Field Name ESQL C sqlca sqlerrd 2 ESQL COBOL SQLERRD 3 OF SQLCA The SQLCODE field of the sqlca structure indicates the result of the CLOSE statement for an insert cursor If all buffered rows are successfully inserted SQLCODE is set to zero If an error is encountered SOLCODE is set to a nega tive error message number See the following chart for the field name for each product Product Field Name ESQL C sqlca sqlcode SQLCODE ESQL COBOL SQLCODE OF SQLCA When SQLCODE is zero the row buffer space is released and the cursor is closed that is you cannot execute a PUT or FLUSH statement that names the cursor until you reopen it Note When you encounter an SQLCODE error there may be a corresponding SQLSTATE error value Check the GET DIA
368. he following examples show literal DATETIME values DATETIME 92 3 6 YEAR TO DAY DATETIME 09 55 30 825 HOUR TO FRACTION DATETIME 92 5 YEAR TO MONTH The following example shows a literal DATETIME value used with the EXTEND function EXTEND DATETIME 1992 8 1 YEAR TO DAY YEAR TO MINUTE INTERVAL 720 MINUTE 3 TO MINUTE Syntax 1 489 Literal Interval Literal Interval Purpose The literal INTERVAL segment is used in the following statements and segments INSERT statement UPDATE statement e Condition segment e Expression segment 1 490 Syntax Literal Interval Syntax INTERVAL p INTERVAL J Numeric Date Field Qualifier J p 1 485 a x WY N A N Rag J space N Ry A hh N Nei A mi N K S A SS N Ney J yyyy is the number of years The maximum number of digits allowed is four unless this is the first field and the precision is specified differently by the INTERVAL field qualifier mo is the number of months The maximum number of digits allowed is two unless this is the first field and the precision is specified differently by the INTERVAL field qualifier dd is the number of days The maximum number of digits allowed is two unless this is the first field and the precision is specified differently by the INTERVAL field qualifier space is literally a space made by pressi
369. he size of existing extents does not change LOCK MODE Clause LOCK MODE Clause LOCK MODE o gt ROW Use the LOCK MODE keywords to change the locking mode of a table The PAGE keyword is the default lock mode it is set if the table is created without using the LOCK MODE clause The following example sets the lock mode to row locking ALTER TABLE items LOCK MODE ROW Syntax 1 33 ALTER TABLE References See the CREATE TABLE DROP TABLE and LOCK TABLE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of data integrity constraints in Chapter 4 and the discussion of creating a database and tables in Chapter 9 1 34 Syntax BEGIN WORK BEGIN WORK Purpose Syntax Usage Use the BEGIN WORK statement to start a transaction a sequence of database operations that are terminated by the COMMIT WORK or ROLLBACK WORK statement BEGIN WORK The following code fragment shows how you might place statements within a transaction BEGIN WORK LOCK TABLE stock UPDATE stock SET unit_price unit_price 1 10 WHERE manu_code KAR DELETE FROM stock WHERE description baseball bat INSERT INTO manufact manu_code manu_name lead_time VALUES LYM LYMAN 14 COMMIT WORK Code fragment showing statements within a transaction Each row affected by an UPDATE DELETE or INSERT statement during a t
370. he start end or a specific point in the execution of a statement If your platform does not provide a system call that returns the current time with subsecond precision the CURRENT function returns a zero for the FRAC TION field Expression In the following example the first statement uses the CURRENT function in a WHERE condition The second statement uses the CURRENT function as the input for the DAY function The last query selects rows whose call_dtime value is within a range from the beginning of 1992 to the current instant DELETE FROM cust_calls WH res_dtime lt CURRENT YEAR TO MINUTE SELECT FROM orders WHER GI DAY ord_date lt DAY CURRENT SELECT FROM cust_calls WHERE call_dtime BETWEEN 1992 1 1 00 00 00 AND CURRENT Literal DATETIME as an Expression The following examples show literal DATETIME as an expression SELECT DATETIME 1993 12 6 YEAR TO DAY FROM customer UPDATE cust_calls SET res_dtime DATETIME 1992 07 07 10 40 YEAR TO MINUTE WHERE customer_num 110 AND call_dtime DATETIME 1992 07 07 10 24 YEAR TO MINUTE SELECT FROM cust_calls WHERE call_dtime DATETIME 1995 12 25 00 00 00 YEAR TO SECOND Literal INTERVAL as an Expression The following examples show literal INTERVAL as an expression INSERT INTO manufact VALUES CAT Catwalk Sports INTERVAL 16 DAY TO DAY SELECT lead_time INTERVAL 5 DAY TO DA
371. he statement block portion of the CREATE PROCEDURE statement is empty no operation takes place when you call the procedure You might use such a procedure in the development stage when you want to establish the existence of a procedure but have not yet coded it CREATE PROCEDURE You must have at least the Resource privilege on a database to create a procedure You cannot use a ROLLBACK WORK statement to undo a CREATE PROCEDURE statement If you roll back a transaction that contains a CREATE PROCEDURE statement the procedure remains and you do not receive an error message DBA Option If you create a procedure using the DBA option it is known as a DBA privileged procedure If you do not use the DBA option the procedure is known as an owner privileged procedure The privileges associated with the execution of a procedure are determined by whether the procedure is created with the DBA keyword See Chapter 14 of the Informix Guide to SQL Tutorial for more information Parameter Syntax and Use Parameter variable SQL Data Type gt name Subset default value LIKE table column REFERENCES BYTE easier oiT NULL column is the column name It is the same data type as the variable The column must exist in the database default value is the default value for the parameter table is the name of the table that contains column variable name is the name of a parameter used in the pro
372. he view in the sysviews system catalog table is updated to reflect the new column name If the column is referenced by a check constraint in the database the text of the check constraint in the syschecks system catalog table is updated to reflect the new column name If you rename a column that appears within a trigger it is replaced with the new name only in the following instances When it appears as part of a correlation name inside the FOR EACH ROW action clause of a trigger e When it appears as part of a correlation name in the INTO clause of an EXECUTE PROCEDURE statement e When it appears as a triggering column in the UPDATE clause 1 294 Syntax RENAME COLUMN When the trigger executes if the database server encounters a column name that no longer exists in the table it returns an error The following example assigns the customer_num column in the customer table the new name of c_num RENAME COLUMN customer customer_num TO c_num You cannot use a ROLLBACK WORK statement to undo a RENAME COLUMN statement that successfully executes If you roll back a transaction that con tains a RENAME COLUMN statement the column retains its new name and you do not receive an error message References See the ALTER TABLE CREATE TABLE and RENAME TABLE statements in this manual Syntax 1 295 RENAME TABLE RENAME TABLE Purpose Syntax Usage 1 296 Syntax Use the RENAME TABLE statement to change the
373. her statements The cursor cursor variable id must conform to the same rules as any identifier as described in the Identifier segment on page 1 469 is an embedded variable name that identifies the cursor in other statements The cursor variable must conform to the same rules as any identifier as described in the Identifier segment on page 1 469 Syntax 1 145 DECLARE Usage 1 146 Syntax statement id is the identifier for a data structure that represents a prepared statement see the PREPARE statement on page 1 273 statement id is an embedded variable name that identifies a data variable structure that represents a prepared statement see the PREPARE statement on page 1 273 The DECLARE statement associates the cursor with a SELECT INSERT or EXECUTE PROCEDURE statement or with the statement identifier statement id or id variable of a prepared statement The DECLARE statement assigns an identifier to the cursor specifies its uses and directs the preprocessor to allocate storage to hold the cursor The DECLARE statement must precede any other statement that refers to the cursor during the execution of the program Used with a SELECT statement the cursor is a data structure that represents a specific location within the active set of rows that the SELECT statement retrieved You associate a cursor with an INSERT statement if you want to add multiple rows to the database in an INSERT operation When used with an
374. hown in the following examples erty Era San o order_date gt 6 12 86 WEEKDAY paid_date WEEKDAY CURRENT 31 UNITS day YEAR ship_date lt YEAR TODAY quantity lt 3 customer_num lt gt 105 customer_num 105 If either expression is null for a row the condition evaluates to false For example if paid_date has a null value you cannot use either of the following statements to retrieve that row SELECT customer_num order_date FROM orders WHERE paid_date SELECT customer_num order_date FROM orders WHERE NOT PAID Syntax 1 407 Condition An IS NULL condition finds a null value as shown in the following example The IS NULL condition is explained fully in IS NULL Condition on page 1 409 SELECT customer_num order_date FROM orders WHERE paid_date IS NULL BETWEEN Condition For a BETWEEN test to be true the value of the expression on the left of the BETWEEN keyword must be in the inclusive range of the values of the two expressions on the right of the BETWEEN keyword Null values do not satisfy the condition You cannot use NULL for either expression that defines the range Some BETWEEN conditions are shown in the following examples order_date BETWEEN 6 1 92 and 9 7 92 zipcode NOT BETWEEN 94100 and 94199 EXTEND call_dtime DAY TO DAY BETWEEN CURRENT INTERVAL 7 DAY TO DAY AND CURRENT lead_time BETWEEN INTERVAL
375. ibutions Update Statistics and Temporary Tables You can use UPDATE STATISTICS on temporary tables You can explicitly update the statistics for a temporary table or build distributions for a tempo rary table by specifying the name of the table If you build distributions on all of the tables in the database by using the FOR TABLE clause without a specific table name distributions will also be built on all of the temporary tables in your session References In the Informix Guide to SQL Tutorial see the discussion of UPDATE STATISTICS in Chapter 13 Syntax 1 397 WHENEVER WHENEVER Purpose Syntax EZ WHENEVER SQLERROR CONTINUE ST aah NOT FOUND GO TO Cae label GOTO label SQLWARNING STOP A ca e A ERROR Usage 1 398 Syntax Use the WHENEVER statement to trap errors and warnings that occur during the execution of other SQL statements PERFORM paragraph __ function name is the name of an SQL API function called when the error or warning condition occurs label is a statement label to which program control transfers when the error or warning condition occurs paragraph name is the name of a COBOL paragraph Using the WHENEVER statement is equivalent to placing an error checking routine after every SQL statement If you do not use a WHENEVER statement in your program to look for errors or warnings and an error is encountered the program execution stops The scope
376. ifferent transaction processing and object naming conventions than does a database that is not ANSI compliant The following example starts an ANSI compliant database named stores6 START DATABASE stores6 WITH LOG IN u myname stores6 log MODE ANSI Transaction Log Name Change You must issue a START DATABASE statement immediately before you archive the database if you plan to change the name or the location of the transaction log Specify the new path to the transaction log in the START DATABASE statement Stopping Logging If you issue the START DATABASE statement with the WITH NO LOG clause against a database that has logging logging is turned off after the statement is run If you run the statement against a database that does not have logging no error is returned This statement cannot be run on an ANSI compliant database References See the CREATE DATABASE and ROLLFORWARD DATABASE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of transaction processing in Chapter 4 and Chapter 6 Syntax 1 377 UNLOAD UNLOAD Purpose Use the UNLOAD statement to write the rows retrieved in a SELECT statement to an ASCII operating system file Syntax DB A SELECT EA UNLOAD TO filename ae eer DELIMITER delimiter delimiter is a quoted character that serves as the delimiter between fields The default delimiter is the vertical bar ASCI
377. ile is overwritten when you issue another SET DEBUG FILE TO statement with the same filename If you invoke a SET DEBUG FILE TO statement with a simple filename on a local database the output file is located in your current directory If your cur rent database is on a remote database server the output file is located in your home directory on the remote database server If you provide a full pathname for the debug file the file is placed in the directory and file specified on the remote database server If you do not have write permissions in the directory you get an error To close the file opened by the SET DEBUG FILE TO statement issue another SET DEBUG FILE TO statement with another filename You can then edit the contents of the first file Syntax 1 351 SET DEBUG FILE TO You can use the SET DEBUG FILE TO statement outside of a procedure to direct the trace output of the procedure to a file You also can use this statement inside a procedure to redirect its own output The following example sends the output of the SET DEBUG FILE TO statement to a file called debugging out SET DEBUG FILE TO debugging out References See the TRACE statement in this manual In the Informix Guide to SQL Tutorial see the discussion of stored procedures in Chapter 14 for a general description of procedures 1 352 Syntax SET DESCRIPTOR SET DESCRIPTOR Purpose Use the SET DESCRIPTOR statement
378. in expression 1 456S YEAR keyword syntax in DATETIME data type 1 4285 in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 13R 1 491S Symbols INFORMIXDIR etc sqlhosts 12 15T percent sign wildcard in Condition segment 1 410S space as delimiter in DATETIME 3 9R in INTERVAL 3 15R asterisk arithmetic operator 1 431S use in SELECT 1 3125 plus sign arithmetic operator 1 431S hyphen as delimiter in DATETIME 3 9R in INTERVAL 3 15R minus sign arithmetic operator 1 431S 4 4R decimal point as delimiter in DATETIME 3 9R in INTERVAL 3 15R ellipses wildcard in Condition segment 1 4115 etc hosts 12 15T etc services 12 15T division symbol arithmetic operator 1 431S slash arithmetic operator 1 431S colon as delimiter in DATETIME 3 9R in INTERVAL 3 15R equals relational operator 2 30T 2 71T question mark as placeholder in PREPARE 1 2738 5 29T naming variables in PUT 1 287S replacing with USING keyword 1 268S wildcard in Condition segment 1 4115 at sign in database name 1 421S backslash as escape character with LIKE 1 410S with MATCHES 1 411S caret wildcard in Condition segment 1 411S _ underscore wildcard in Condition segment 1 410S 1 concatenation operator 1 432S Index 51 52 Index Reader Response Card Informix Guide to SQL Syntax Version 6 0 Dear Reader At Informix Software
379. in the pathname of the directory from which you ran the dbaccessdemo6 script 5 To give someone else the permissions to access the command files in your directory use the UNIX chmod command 6 To give someone else the access to the database that you have created grant them the appropriate privileges using the GRANT statement To remove privileges use the REVOKE statement The GRANT and REVOKE statements are described in Chapter 1 of this manual New Features in Informix Version 6 0 Products That Use SOL 14 Introduction The Introduction to each Version 6 0 product manual contains a list of new features for that product The Introduction to each manual in the Version 6 0 Informix Guide to SQL series contains a list of new SQL features A comprehensive listing of all the new features for Version 6 0 Informix products is found in the Release Notes file called SERVERS_6 0 This section highlights the major new features implemented in Version 6 0 of Informix products that use SQL e Native Language Support Native Language Support NLS makes Informix Version 6 0 products adaptable to various European cultural and language environments with out requiring changes to the application source code When appropriate environment variables are set to activate NLS and specify a locale Informix products can properly collate strings that contain foreign characters accept money and decimal input and print dates and times in the format requi
380. information on the sqlda structure and descriptors You can modify the system descriptor area information and use it in statements that support a USING SOL DESCRIPTOR clause such as EXECUTE FETCH OPEN and PUT You must modify the system descriptor area to show the address in memory that is to receive the described value You can change the data type to another compatible type This change causes data conversion to take place when the data is fetched In addition to Chapter 5 of the Informix Guide to SQL Tutorial see the manual for your embedded language product for further information about inter preting and using the data contained in the sqlda data structure and the sys tem descriptor area USING SQL DESCRIPTOR Clause 1 164 Syntax The USING SQL DESCRIPTOR clause lets you store the description of a SELECT INSERT or EXECUTE PROCEDURE list in a system descriptor area created by an ALLOCATE DESCRIPTOR statement You can obtain information about the resulting columns of a prepared statement through a system descriptor area Use the USING SQL DESCRIPTOR keywords and a descriptor to point to a system descriptor area instead of to an sqlda structure The DESCRIBE statement sets the COUNT field in the system descriptor area to the number of values in the SELECT EXECUTE PROCEDURE or INSERT list If COUNT is greater than the number of item descriptors occurrences in the system descriptor area the system returns an error Otherwise th
381. ing Deletes Cascading deletes can be used for most deletes The only exception is correlated subqueries In correlated subqueries the subquery or inner SELECT is correlated when the value it produces depends on a value pro duced by the outer SELECT statement that contains it If you have imple mented cascading deletes you cannot write deletes that use a child table in the correlated subquery You receive an error when you attempt to delete from a query that contains such a correlated subquery See Chapter 4 of the Informix Guide to SQL Tutorial for a detailed discussion about cascading deletes The CHECK Clause 1 98 Syntax CHECK Clause Condition gt CHECK p 1 404 p Check constraints allow you to designate conditions that must be met before data can be assigned to a column during an INSERT or UPDATE statement If a row evaluates to false for any of the check constraints defined on a table during an insert or update the database server returns an error CREATE TABLE Check constraints are defined using search conditions The search condition cannot contain subqueries aggregates host variables rowids the CURRENT USER SITENAME DBSERVERNAME or TODAY functions or stored procedure calls Defining Check Constraints at the Column Level If you define a check constraint at the column level the only column that the check constraint can check against is the column itself In other words th
382. ing blobspace is a quoted string constant that specifies a family name or variable name in the optical family Family name or variable name For additional information about optical families see the INFORMIX OnLine Optical User Manual is ignored Positive integer is the maximum length characters for a VARCHAR which ranges from 1 to 255 is the total number of significant digits in a decimal or money type Integer between 1 and 32 inclusive is the amount of space in characters reserved for a VARCHAR even if the actual data is shorter than reserve The range is from 0 to 255 but is less than the maximum size for VARCHAR is the number of digits to the right of the decimal point ranging between 1 and precision Data Type size is the number of characters in the column For OnLine databases the integer is between 1 and 32 767 inclusive For SE databases the integer is between 1 and 32 511 start is the starting number for values in a SERIAL column The integer is greater than 0 and less than 2 147 483 647 Usage For more information see the discussion of all data types in Chapter 3 of the Informix Guide to SQL Reference Syntax 1 427 DATETIME Field Qualifier DATETIME Field Qualifier Purpose Syntax Usage 1 428 Syntax The DATETIME field qualifier specifies the largest and smallest unit of time in a DATETIME column or value Use the DATETIME field qualifier with the following segments e Dat
383. ing data types 3 23R description of 3 11R fixed point 9 10T floating point 3 11R 9 10T signalled in SQLAWARN 5 12T syntax 1 425S using as default value 1 195 1 895 Decimal point as delimiter in DATETIME 3 9R as delimiter in INTERVAL 3 15R DECLARE statement cursor characteristics 1 149S cursor types 1 148S cursors with prepared statements 1 154S cursors with transactions 1 155S definition and use hold cursor 1 150S insert cursor 1 149S 1 157S procedure cursor 1 148S scroll cursor 1 149S select cursor 1 148S sequential cursor 1 149S update cursor 1 1485 1 1525 description of 5 20T FOR INSERT clause 6 8T FOR UPDATE 6 15T insert cursor 1 148S insert cursor with hold 1 157S procedure cursor 1 1485 restrictions with SELECT with ORDER BY 1 340S SCROLL keyword 5 23T syntax 1 145S update cursor 1 1485 updating specified columns 1 153S use with concatenation operator 1 432S with FOR UPDATE keywords 1 148S WITH HOLD clause 7 19T with SELECT 1 321S Default assumptions for your environment 4 6R DEFAULT keyword 1 169S in the CONNECT statement 1 465 Default value description of 4 19T specifying with ALTER TABLE 1 19S with CREATE TABLE 1 888 Deferred checking 1 3495 DEFERRED keyword in the SET CONSTRAINTS statement 1 349S DEFINE statement in stored procedures 14 17T placement of 2 85 syntax 2 75 DELETE keyword syntax in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S Delete privilege 1 235S 1
384. ing values with 14 21T associating cursor with DECLARE 1 148S in FOREACH 2 208 in triggered action 1 122S using 14 9T with INTO keyword 1 1985 EXECUTE statement and sqlca record 1 186S description of 5 31T parameterizing a statement 1 186S syntax 1 184S USING DESCRIPTOR clause 1 1885 with concatenation operator 1 432S with USING keyword 1 186S Existence dependency 8 9T EXISTS keyword beginning a subquery 1 330S in a WHERE clause 3 33T use in condition subquery 1 4145 11 27T EXIT statement exiting a loop 14 23T syntax 2 148 EXP function syntax in expression 1 451S use in expression 1 451S Explicit temporary table 1 100S Exponential function EXP function 1 451S Exponential function See EXP function Expression date oriented 2 56T description of 2 46T display label for 2 49T in UPDATE 1 3875 ordering by 1 339S Expression segment aggregate expressions 1 4625 column expressions 1 433S combined expressions 1 4675 constant expressions 1 4365 expression types 1 4315 function expressions 1 4435 in SPL expressions 1 468S syntax 1 431S EXTEND function syntax in expression 1 454S use in expression 1 456S with DATE DATETIME and INTERVAL 3 26R 3 28R 2 56T 2 61T extension dat Intro 11R dbs Intro 11R idx Intro 11R lok 1 370S Extension checking specifying with DBANSIWARN 4 15R Extension to SQL symbol for Intro 75 with ANSI compliant database 1 14R Extent changing size of for system table 2 9R description of 10
385. ing with cursor 1 148S definition of 1 2745 releasing 1 274S syntax in DECLARE 1 145S in DESCRIBE 1 162S in EXECUTE 1 1845S in FREE 1 2075 in PREPARE 1 2735 use in DECLARE 1 154S in FREE 1 2085 in PREPARE 1 2745 Statement types 1 5S Statement variable name definition 1 190S Static SQL 5 5T STATUS FOR keywords in INFO statement 1 2445 STATUS variable 4GL 5 11T Status displaying with INFO statement 1 2445 stock table in stores6 database columns in A 4R STOP keyword in the WHENEVER statement 1 398S 1 402S Storage device 12 6T Stored procedure altering 14 13T as triggered action 1 128S 15 10T branching 14 22T BYTE and TEXT data types 2 95 2 138 checking references 1 1295 comments in 14 6T creating from an embedded language 14 5T creating from DB Access 14 5T cursors with 2 205 DBA privileged use with triggers 1 129S 14 13T debugging 2 425 14 11T default privileges 14 14T DEFINE statement 14 17T definition of 14 3T displaying contents 14 9T displaying documentation 14 9T executing 14 9T general programming 1 17T granting privileges on 1 237S 11 12T 14 15T handling multiple rows 2 398 header 2 8S 14 25T in SELECT statements 1 315S 2 67T in WHEN condition 1 122S introduction to 14 3T looping 14 23T name confusion with SQL functions 14 21T naming output file for TRACE statement 1 351S owner privileged 1 1295 14 13T privileges 1 129S privileges necessary at execution 14 14T program fl
386. int or edit e Trailing blanks are retained in VARCHAR fields e Do not use the following characters as delimiting characters in the UNLOAD TO file 0 9 a f A F newline or backslash Syntax 1 379 UNLOAD The following statement unloads rows from the customer table where the value of customer_num is greater than or equal to 138 and puts them ina file named cust_file UNLOAD TO cust_file DELIMITER SELECT FROM customer WHERE customer_num gt 138 The output file cust_file appears as shown in the following example 138 Jeffery Padgett Wheel Thrills 3450 El Camino Suite 10 Palo Alto CA 94306 139 Linda Lane Palo Alto Bicycles 2344 University Palo Alto CA 94301 415 323 5400 DELIMITER Clause Use the DELIMITER clause to identify the delimiter that separates the data contained in each column in a row in the output file If you omit this clause DB Access checks the DBDELIMITER environment variable If the DBDELIMITER variable has not been set the default delimiter is the vertical bar ASCII 124 See Chapter 4 of the Informix Guide to SQL Refer ence for information about setting the DBDELIMITER environment variable You can specify the TAB CTRL I or lt blank gt ASCII 32 as the delimiter symbol You cannot use the following as the delimiter symbol Backslash Newline CTRL J Hex numbers 0 9 a f A F The following statement specifies the semicolon as th
387. ion Statement right Block END expression p 1 72 FOR N STEP increment expression J 2 16 SPL Statements a left expression expression increment expression left expression right expression variable name LC expression right expression C increment STEP expression is a numeric or character value The data type of expression must match the data type of the variable name You can use the output of a SELECT statement as an expression is a positive or negative value by which variable name is to be incremented The increment expression cannot evaluate to zero is the starting expression of a range The left expression must match the data type of the variable name is the ending expression in the range is a variable that is already defined and valid within this statement block Usage FOR All expressions are computed before the FOR statement executes If one or more of the expressions are variables and their values are changed during the loop the change has no effect on the iterations of the loop The FOR loop terminates when variable name takes on the values of each element in the expression list or range in succession or when it encounters an EXIT FOR statement An error is generated if an assignment within the body of the FOR statement attempts to modify the value of variable name Using the TO Keyword to Define a Range The TO key
388. ipcode file_variable dbg Date TODA You cannot use the concatenation operator in an ESQL only statement The ESQL only statements are found in the following list ALLOCATE DESCRIPTOR FETCH CLOSE FLUSH CONNECT TO FREE DEALLOCATE DESCRIPTOR GET DESCRIPTOR DECLARE OPEN DESCRIBE PREPARE DISCONNECT PUT EXECUTE SET CONNECTION EXECUTE IMMEDIATE SET DESCRIPTOR Expression Column Expressions The possible syntax for column expressions is as shown in the following diagram column k Tabl f ai able Nooo Ps he p 1 506 Ne first last N alias Rowip View J Name p 1 510 Synonym S Name eet p 1 504 alias is used in a SELECT statement in any clause but the SELECT and FROM clauses it is the alternative name for the table as established in the FROM clause column name is the name of the column that you are selecting first is the position of the first character of the column CHAR VARCHAR NCHAR NVARCHAR BYTE or TEXT last is the position of the last character of the portion that you are selecting The following examples show column expressions company items price cat_advert 1 15 Syntax 1 433 Expression Use a table or alias name whenever it is necessary to distinguish between columns that have the same name but are in different tables The SELECT statements shown in the following example use customer_num from the cus t
389. ired For Order By 1 joe customer INDEX PATH Filters joe customer company MATCHES Sport 1 Index Keys customer_num Lower Index Filter joe customer customer_num gt 110 Upper Index Filter joe customer customer_num lt 115 SET EXPLAIN The following example shows the SET EXPLAIN output for a multiple table query SELECT FROM customer orders items WHERE customer customer_num orders customer_num AND orders order_num items order_num Estimated Cost 20 Estimated of Rows Returned 69 1 joe orders SEQUENTIAL SCAN 2 joe customer INDEX PATH 1 Index Keys customer_num Lower Index Filter joe customer customer_num joe orders customer_num 3 joe items INDEX PATH 1 Index Keys order_num Lower Index Filter joe items order_num joe orders order_num Using SET EXPLAIN With SET OPTIMIZATION If you SET OPTIMIZATION to low the output of SET EXPLAIN displays the following uppercase string QUERY LOW If you SET OPTIMIZATION to high the output of SET EXPLAIN displays the following uppercase string QUERY Reference In the Informix Guide to SQL Tutorial see the discussion of SET EXPLAIN and the optimizer discussion in Chapter 13 Syntax 1 365 SET ISOLATION SET ISOLATION Purpose Syntax Usage 1 366 Syntax Use the SET ISOLATION statement with the INFORMIX OnLine Dynamic Server database server to define the degree of concurrency among processes t
390. is correct the database server returns a syntax error The preceding pages show existing syntactic workarounds for several situations You can use the AS keyword to provide a workaround for the exceptions You can use the AS keyword in front of column labels or table aliases The AS keyword is an Informix extension to SQL The following example uses the AS keyword with a column label column name AS display label FROM table name The following example uses the AS keyword with a table alias SELECT select list FROM table name AS table alias Using AS with Column Labels 1 476 Syntax The examples in this section show workarounds that use the AS keyword with a column label The first two examples show how you can use the key word UNITS or YEAR MONTH DAY HOUR MINUTE SECOND or FRACTION as a column label Using units as a column label causes the following example to fail because the database server interprets it as a DATETIME qualifier for the column named mycol SELECT mycol units FROM mytab The workaround in the following example includes the AS keyword SSELECT mycol AS units FROM mytab The following examples show how the AS or FROM keyword can be used as a column label Identifier Using as as a column label causes the following example to fail because the database server interprets as as identifying from as a column label and thus finds no required FROM clause SELECT mycol as f
391. is done only once For more information see the PREPARE statement on page 1 273 UPDATE exec sql begin declare section char fname 32 lname 32 int low high float discount char answer exec sql end declare section main exec sql connect to stores6 exec sql prepare sel_stmt from select from customer where cust_num between and for update exec sql declare x cursor for sel_stmt printf nEnter lower limit customer number scanf d amp low printf nEnter upper limit customer number scanf Sd amp high exec sql open x using low high exec sql prepare u from update customer set discount 0 1 where current of x while 1 exec sql fetch x into fname lname discount if SQLCODE SQLNOTFOUND break printf nUpdate 10s 10s y n fname lname if answer getch y exec sql execute u exec sql close x Note You can use an update cursor to perform updates that are not possible with the UPDATE statement An update cursor is a sequential cursor that is associated with a SELECT statement that is declared with the FOR UPDATE keyword For more information on the update cursor see page 1 148 References See the DECLARE INSERT OPEN and SELECT statements in this manual In the Informix Guide to SQL Tutorial see the discussion of the UPDATE statement in Chapter 6 Syntax 1 391 UPDATE STATISTICS UPDATE STATIS
392. is larger than last last is a qualifier that specifies the last field in the result month integer is an expression as defined on page 1 430 that evaluates expression to an integer between 1 and 12 as appropriate for the month non date is an expression as defined on page 1 430 that evaluates expression to a CHARACTER DATETIME or INTEGER value that can be converted to a DATE data type year integer is an expression as defined on page 1 430 that evaluates expression to a four digit integer DATE Function The DATE function returns a DATE type value that corresponds to the character expression with which you call it The argument can be any expres sion that can be converted to a DATE value usually a CHAR DATETIME or INTEGER value The WHERE clauses in the following example achieve the same end converting a string to a date WHERE order_date lt DATE 12 31 92 WHERE order_date lt DATE 365 DAY Function The DAY function returns an integer that represents the day of the month The following example uses the DAY function with the CURRENT function to compare column values to the current day of the month WHERE DAY order_date gt DAY CURRENT Syntax 1 455 Expression 1 456 Syntax MONTH Function The MONTH function returns an integer that corresponds to the month portion of its type DATE or DATETIME argument The following example returns a number 1 through 12 to indicate the month in whi
393. it_amt columns must equal each other or the insert or update fails Syntax 1 99 CREATE TABLE TEMP TABLE Option 1 100 Syntax Temporary tables created with the CREATE TEMP TABLE statement are called explicit temporary tables Explicit temporary tables can also be created with the SELECT INTO TEMP statement When an application creates an explicit temporary table it exists until one of the following occurs The application terminates The application closes the database in which the table was created In this case the table is dropped only if the database does transaction logging and the temporary table was not created with the WITH NO LOG option e The application closes the database in which the table was created and opens a database in a different database server a second OnLine or an SE database server When any of these events occur the temporary table is deleted The INFO statement and the Info Menu Option cannot be used with temporary tables Temporary table names must be different from existing table view or synonym names in the current database however they need not be different from other temporary table names used by other users Temporary tables that are created as a part of processing are called implicit temporary tables Implicit temporary tables are discussed in the INFORMIX OnLine Dynamic Server Administrator s Guide You can specify where temporary tables are created with the CREATE TEM
394. ith the DBDATE and LC_TIME environment variables See Chapter 4 of the Informix Guide to SQL Reference for more information about environment variables MONEY values are unloaded with no leading currency symbol NULL columns are unloaded by placing no characters between the delimiters Number data types are displayed with no leading blanks INTEGER or SMALLINT zero are represented as 0 and FLOAT SMALLFLOAT DECIMAL or MONEY zero are represented as 0 00 If you are using NLS you can specify a different format for MONEY with the LC_MONETARY environment variable See Chapter 4 of the Informix Guide to SQL Reference for more information about environment variables DATETIME and INTERVAL values are represented in character form showing only their field digits and delimiters No type specification or qualifiers are included in the output The following pattern is used yyyy mm dd hh mi ss fff omitting fields that are not part of the data Do not use the backslash character as a field separator or UNLOAD delimiter It serves as an escape character to inform the UNLOAD command that the next character is to be interpreted as part of the data If you are unloading files containing VARCHAR or BLOB data types note the following information BYTE items are written in hexadecimal dump format with no added spaces or new lines Consequently the logical length of an unloaded file that contains BYTE items can be very long and very difficult to pr
395. ity 5 5R Collation COLLCHAR environment variable 4 45R LC_COLLATE environment variable 4 50R simultaneous and performance 1 20R with NLS activated 1 15R Collation order and NLS 2 25T COLLCHAR environment variable 1 16R 4 45R Colon as delimiter in DATETIME 3 9R as delimiter in INTERVAL 3 15R Color setting INFORMIXTERM for 4 38R Column changing data type 3 23R creating with NLS 1 19R defined 2 5T defining 8 20T defining as foreign key 1 935 defining as primary key 1 93S description of 1 12T displaying information for 1 2425 in relational model 1 12T 8 20T in stores6 database A 2R to A 6R inserting into 1 246S label on 3 48T modifying with ALTER TABLE 1 278 naming conventions 1 875 1 1025 1 294S naming allowable characters 1 469S naming in ALTER TABLE 1 17S naming in CREATE TABLE 1 87S number allowed when defining constraint 1 865 putting a constraint on 1 86S referenced and referencing 1 225 1 94S renaming 1 294S specifying check constraint for 1 98S specifying with CREATE TABLE 1 875 virtual 1 137S See also Constraint See also Data Type segment Column expression in SELECT 1 314S syntax 1 433S See also Expression segment Column filter See Filter expression Column name allowable characters 1 469S in UPDATE clause 1 1145 naming in ALTER TABLE 1 175 using functions as names 1 472S using keywords as names 1 473S when qualified 1 1245 Column number 2 24T effect on triggers 1 115S Column value in trigg
396. ive actions If you have installed this product you can print the PostScript files on a PostScript Introduction 11 The Demonstration Database printer The PostScript error messages are distributed in a number of files of the format errmsg1 ps errmsg2 ps and so on These files are located in the INFORMIXDIR msg directory The Demonstration Database 12 Introduction The DB Access utility which is provided with your Informix database server products includes a demonstration database called stores6 that contains information about a fictitious wholesale sporting goods distributor The sam ple command files that make up a demonstration application are also included Most of the examples in this manual are based on the stores6 demonstration database The stores6 database is described in detail and its contents are listed in Appendix A of the Informix Guide to SQL Reference The script that you use to install the demonstration database is called dbaccessdemo6 and is located in the INFORMIXDIR bin directory The data base name that you supply is the name given to the demonstration database If you do not supply a database name the name defaults to stores6 Follow these rules for naming your database e Names for databases can be up to 18 characters long for INFORMIX OnLine Dynamic Server databases and up to 10 characters long for INFORMIX SE databases The first character of a name must be a letter or an underscore _ e
397. ively For example the index name may be something like this 121_13 quotes used to show the space The constraint name must be unique within the database If you do not spec ify a constraint name the database server generates one for the sysconstraints system catalog table using the following template lt constraint type gt lt tabid gt _ lt constraint id gt In this template constraint type is the letter u for unique or primary key constraints r is for referential constraints or c is for check constraints For example the constraint name for a unique constraint might look like this u111_14 If the name conflicts with an existing identifier the database server returns an error and you must then supply a constraint name Column Definition Option Column Definition gt column Data Type T yo p 1 424 pi DN ae DEFAULT NOT NULL Golur revel clause Definition p p 1 91 column is a valid identifier for columns The column name must be unique within a table but you can use the same names in different tables in the same database For additional Syntax 1 87 CREATE TABLE information about column naming see Identifier on page 1 469 Use the column definition portion of the CREATE TABLE statement to list the name data type default values and constraints of a single column as well as to indicate whether the column does not allow duplicate values
398. l constraint you must have the DBA or References privilege on either the referenced columns or the referenced table To drop a constraint in a database you must have the DBA privilege or be the owner of the constraint If you are the owner of the constraint but not the owner of the table you must have Alter privilege on the specified table You do not need the References privilege to drop a constraint Syntax 1 15 ALTER TABLE 1 16 Syntax Altering a table on which a view depends may invalidate the view You can use one or more of the ADD DROP MODIFY ADD CONSTRAINT or DROP CONSTRAINT clauses and you can place them in any order You can use only one MODIFY NEXT SIZE clause or LOCK MODE clause The actions are performed in the order specified When any of the actions fail the entire operation is cancelled You cannot use a ROLLBACK WORK statement to undo an ALTER TABLE statement When you roll back a transaction that contains an ALTER TABLE statement the table remains altered you do not receive an error message ALTER TABLE ADD Clause ADD Clause Add Column me ADD Clause a J Add Column Clause Add Column Clause new column Data Type gt name p 1 424 DEFAULT NOT 4 Clause NULL New Column p 1 18 Constraint Definition p 1 20 column BEFORE name column name is the name of an existing column before which the new
399. l the informa tion that the database environment associates with this name Reestablishing a connection to a database environment is comparable to establishing the ini tial connection except that it typically avoids authenticating the user s per missions again and it saves the cost of resources associated with the initial connection necessary information is available in the associated connection context SET CONNECTION If the application did not use a connection name in the initial CONNECT statement you must use database environment as the connection name For example the following SET CONNECTION statement uses database environment for the connection name because the CONNECT statement does not use connection name CONNECT TO stores6 CONNECT TO ashokr SET CONNECTION to stores6 If a connection to a database server was assigned a connection name however you must use the connection name to reconnect to the database server An error is returned if you use database environment rather than the connection name when a connection name exists The DEFAULT Option You can use the DEFAULT option to reestablish a DEFAULT connection The DEFAULT connection is one of the following connections e An explicit DEFAULT connection a connection established with the CONNECT DEFAULT statement e An implicit connection any connection made using the DATABASE CREATE DATABASE or START DATABASE statements See The DE
400. ld remain open when a transaction closes committed or rolled back Updating or Deleting Rows Identified by Cursor Name To update or delete the current row of cursor name use the WHERE CURRENT OF cursor name clause Calling a Procedure in the FOREACH Loop The called procedure can return zero or more rows The type and count of each variable in the variable list must match each value returned by the called procedure Subset of Expressions Allowed in the Procedure Parameters You can use any expression as a procedure parameter except an aggregate expression If you use a subquery or procedure call the subquery or procedure must return a single value of the appropriate type and size For the full syntax of an expression see page 1 430 SPL Statements 2 23 IF IF Purpose Use an IF statement to create a branch within a procedure Syntax Condition IF p 4 404 H THEN END IF a 7 IF Statement List p 2 26 Condition IF Statement IF Statement ELIF p 1 404 THEN List ELSE List p 2 26 p 2 26 Usage The condition stated in the IF clause is evaluated If the result is true then the statements following the THEN keyword executes If the result is false and an ELIF clause exists the statements following the ELIF clause execute If no ELIF clause exists or if the condition in the ELIF clause is not true the statements following the ELIF keyword execute
401. le so you issue the following statement REVOKE ALL ON items FROM tom When you try to revoke Jim s privileges with a similar statement however the database server returns an error as shown in the following example REVOKE SELECT UPDATE ON items FROM jim 580 Cannot revoke permission Because the database server record shows the original grantor as Tom you cannot revoke the privilege ALthough you are the table owner you cannot revoke a privilege granted by another user Privileges on a View You must explicitly grant access privileges on the view to users because no automatic grant is made to public as is the case with a newly created table When creating a view if you do not own the underlying tables you must have at least the Select privilege on the table or columns As view creator the privileges you have on the underlying table apply to the view built on the table You do not receive any other privileges or the ability to grant any other Syntax 1 239 GRANT privileges because you own the view on the table If the view meets all the requirements for updating any Delete Insert or Update privileges you have on the table also apply to the view You can grant or revoke privileges on a view only if you are the owner of the underlying tables or if you received these privileges on the table with the right to grant them the WITH GRANT OPTION keyword You cannot grant Index Alter or References privilege
402. lete is not yet committed or in the process of being deleted Under these isolation levels an application can read a deleted blob when certain conditions exist Using DB Access you see more lock conflicts with higher levels of isolation For example if you use cursor stability you see more lock conflicts than if you use committed read SET ISOLATION If you use a scroll cursor in a transaction you can force consistency between your temporary table and the database table either by setting the isolation level to Repeatable Read or by locking the entire table during the transac tion If you use a scroll cursor with hold in a transaction you cannot force consistency between your temporary table and the database table A table level lock or locks set by Repeatable Read are released when the transaction is completed but the scroll cursor with hold remains open beyond the end of the transaction This lets you modify released rows as soon as the trans action ends creating the possibility that the retrieved data in the temporary table can be inconsistent with the actual data References See the CREATE DATABASE and SET LOCK MODE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of isolation levels in Chapter 7 Syntax 1 369 SET LOCK MODE SET LOCK Purpose Syntax Usage 1 370 Syntax MODE Use the SET LOCK MODE statement to define how the database server handles a process that t
403. lumn the maximum length of the string is 256 bytes If you insert a value greater than 256 the database server returns an error If you are using variables you can insert quoted strings longer than 256 bytes into a table Value and Column Type Compatibility NLS Although the values you insert do not have to be the same data type as the columns receiving them the value type and column type must be compati ble You can insert only characters into CHAR columns and only numbers or characters representing number data into number columns The following example inserts values into the columns of the customer table INSERT INTO customer VALUES 0 Nadia Broadam Ski amp Stuff 89 Coniston Road NULL Short Hills NJ 07079 201 457 4100 The database server makes every effort to perform data conversion If the data cannot be converted the INSERT operation fails Data conversion also fails if the target data type cannot hold the value specified For example you cannot insert the integer 123456 into a column defined as a SMALLINT data type because this data type cannot hold a number that large When NLS is enabled the following example inserts values containing foreign characters into NCHAR columns INSERT INTO abonn s VALUES 0 P tain Ren 1221 Bd Hassan II Rabat Maroc Inserting Values into SERIAL Columns If you want to insert consecutive serial values into a SERIAL column in th
404. m to the same rules as any identifier as described in the Identifier segment on page 1 469 statement is the name of an SQL API character variable that contains id variable the SQL statement identifier The id variable and the identifier it contains must conform to the same rules as any identifier as described in the Identifier segment on page 1 469 variable name isan INFORMIX ESQL host variable that contains the text of the SQL statement to be prepared The PREPARE statement permits your program to assemble the text of an SQL statement at run time and make it executable This dynamic form of SQL is accomplished in three steps 1 A PREPARE statement accepts statement text as input either as a quoted string or stored within a character variable Statement text can contain question mark placeholders to represent values that are to be defined when the statement is executed 2 An EXECUTE or OPEN statement can supply the required input values and execute the prepared statement once or many times 3 Resources allocated to the prepared statement can be released later using the FREE statement Syntax 1 273 PREPARE The number of prepared objects in a single program is limited by the available memory This includes both statement identifiers named in PRE PARE statements and cursor declarations that incorporate SELECT EXECUTE PROCEDURE or INSERT statements To avoid exceeding the limit use a FREE statement to release some sta
405. m call_dtime c_num_cus_ix velma dupls No customer_num Displaying Privileges References and Status You can use keywords in your INFO statement to display information about the access privileges including the References privilege or status of a table 1 242 Syntax INFO Use the ACCESS FOR or PRIVILEGES FOR keywords to display six of the user access privileges for a specified table The following examples show an INFO statement and the resulting display of user privileges for a table INFO PRIVILEGES FOR cust_calls INFO statement requesting privileges information User Select Update Insert Delete Index Alter public All All Yes Yes Yes No Display of privileges information Use the REFERENCES FOR keywords to display the References privilege for users for the columns of a specified table The following examples show an INFO statement and the resulting display INFO REFERENCES FOR newtable INFO statement requesting References privilege information User Column References betty coll col2 col3 wilma All public None Display of References privilege information The output indicates that the user betty can reference columns col1 col2 and col3 of the specified table the user wilma can reference all the columns in the table and public cannot access any of the columns in the table If you want information about database level privileges you must use a SELECT statement to access the sysusers sys
406. m is an SQL identifier If you are creating the synonym the name of the synonym must be unique within a database The name cannot be the same as table names temporary table names or view names It is possible to have a public and private synonym with the same name If you are creating the synonym the combination owner name must be unique within a database The owner name is case sensitive In an ANSI compliant database if you do not use quotes around the owner name the name of the table owner is stored in uppercase letters For more information see the discussion of case sensitivity in ANSI compliant databases on page 1 508 Syntax 1 505 Table Name Table Name Purpose Use the Table Name segment in the following statements to specify the name of a table ALTER TABLE CREATE AUDIT CREATE INDEX CREATE SYNONYM CREATE TABLE DELETE DROP AUDIT DROP TABLE GRANT INSERT LOCK TABLE RECOVER TABLE RENAME COLUMN RENAME TABLE REVOKE SELECT UNLOCK TABLE UPDATE UPDATE STATISTICS 1 506 Syntax Table Name Syntax Identifier p 1 469 ce database eZ dbservername uf database is the name of the database in which the table resides dbservername is the name of the INFORMIX OnLine Dynamic Server database server that is home to database The sign is a literal character that you must use to introduce the database server name owner is the user name of the owner of the table If you are using an A
407. manipulation statement The Action Statements 1 122 Syntax The triggered action statements can be INSERT DELETE UPDATE or EXECUTE PROCEDURE statements If a triggered action list contains multiple statements these statements execute in the order in which they appear in the list In INFORMIX SE all objects referenced in the triggered actions must be in the current database CREATE TRIGGER Achieving a Consistent Result To guarantee that the triggering statement returns the same result with and without the triggered actions make sure that the triggered actions in the BEFORE and FOR EACH ROW sections do not modify any table referenced in the following clauses WHERE clause SET clause in the UPDATE statement SELECT clause EXECUTE PROCEDURE clause in a multiple row INSERT statement Using Keywords If you use the keywords INSERT DELETE UPDATE or EXECUTE as an identifier in any of the following clauses inside a triggered action list you must qualify them by the owner name or the table name or both FROM clause of a SELECT statement INTO clause of the EXECUTE PROCEDURE statement GROUP BY clause SET clause of the UPDATE statement You get a syntax error if these keywords are not qualified when you use these clauses inside a triggered action If you use the keyword as a column name it must be qualified by the table name for example table update If both the table name and the column name
408. mber of rows that satisfy the WHERE clause The following example finds how many Hero products are stocked SELECT COUNT FROM stock WHERE manu_code HRO If the SELECT statement contains a GROUP BY clause the COUNT keyword reflects the number of values in each group The following example is grouped by the first name the rows are selected if the database server finds more than one occurrence of the same name SELECT fname COUNT FROM customer GROUP BY fname HAVING COUNT gt 1 If the value of one or more rows is null the COUNT keyword includes the null columns in the count unless the WHERE clause explicitly omits them Syntax 1 463 Expression AVG Keyword The AVG keyword returns the average of all values in the specified column or expression You can apply the AVG keyword only to number columns If you use the DISTINCT keyword the average mean is greater than only the distinct values in the specified column or expression The query in the following example finds the average price of a helmet SELECT AVG unit_price FROM stock WHERE stock_num 110 Nulls are ignored unless every value in the specified column is null If every column value is null the AVG keyword returns a null for that column MAX Keyword The MAX keyword returns the largest value in the specified column or expression Using the DISTINCT keyword does not change the results The query in the following example find
409. ment is complete A branch below the main line indicates an optional path A loop indicates a path that can be repeated Punctuation along the top of the loop indicates the separator symbol for list items Introduction 7 How to Use This Manual A gate 4 in an option indicates that you can rae only use that option once even if it is within a column key larger loop In Chapter 1 of this manual icons that appear in the left margin indicate that the text inside the gray box is valid only for some products or under certain conditions In addition to the icons described in the preceding list you might encounter the following icons in the left margin This icon indicates that the functionality described by the text in the gray box is valid only if your database is ANSI compliant X O This icon indicates that the functionality described by the text in the gray box conforms to X Open standards for dynamic SQL This functionality is available when you compile your SQL API with the xopen flag 8 Introduction How to Use This Manual Figure 1 shows the elements of a syntax diagram for the CREATE DATABASE statement CREATE DATABASE database name ee IN dbspace OL Log Clause Keywords Subdiagrams Figure 1 Reference Boxes i Terminator Signals Variables SE Log Clause OL Log Clause WITH c J LOG p BUFFERED LOG MODE ANSI Punctuation SE L
410. ments SELECT DELETE within the Condition segment UPDATE within the Condition segment EXECUTE PROCEDURE Expression Syntax Column NS Expressions J i amp Ee f Constant Expressions p 1 436 Function Expressions p 1 443 Aggregate Expressions p 1 462 Procedure Call Nd Expressions p 1 468 variable name Na procedure variable name Expression variable name is the name of a program variable or a host variable that contains a value procedure is the name of a valid variable that is defined in the variable name procedure Usage You can combine expressions by connecting them with arithmetic operators for addition subtraction multiplication and division Syntax 1 431 Expression You cannot use an aggregate expression in a condition that is part of a WHERE clause unless the aggregate expression is used within a subquery Concatenation Operator 1 432 Syntax You can use the concatenation operator to concatenate two expressions For example the following are some possible concatenated expression combinations The first example concatenates the zipcode column to the first three letters of the Iname column The second example concatenates the suf fix dbg to the contents of a host variable called file_variable The third example concatenates the value returned by the TODAY function to the string Date lname 1 3 z
411. ments 1 148S 5 32T WITH HOLD 7 18T 10 34T See also CLOSE statement See also Hold cursor See also Insert cursor See also OPEN statement See also Scroll cursor See also Select cursor See also Sequential cursor See also Update cursor Cursor Stability isolation level 1 3675S 7 11T CURSOR STABILITY keywords syntax in SET ISOLATION 1 366S Cursory procedure 2 215 customer table in stores6 database columns in A 2R cust_calls table in stores6 database columns in A 5R Cyclic query 4 22T D Daemon 12 14T Data connecting to 12 12T containing foreign characters 1 19R inserting with the LOAD statement 1 255S integrity 12 20T Data access statements 1 6S Data definition statements 1 5S 5 34T Data distributions confidence 1 397S creating on filtered columns 13 9T 13 29T on temporary tables 1 397S RESOLUTION 1 396S 1 397S use with optimizer 13 9T DATA field setting with SET DESCRIPTOR 1 3575 Data integrity 4 22T to 4 25T 12 20T statements 1 6S Data manipulation statements 1 65 Data model attribute 8 14T building 8 3T to 8 33T defining relationships 8 8T denormalizing 10 26T to 10 32T description of 1 3T 8 3T entity relationship 8 4T many to many relationship 8 11T one to many relationship 8 11T one to one relationship 8 11T See also Relational model telephone directory example 8 6T Data protection with OnLine 12 19T Data replication 12 19T Data type automatic conversions 5 15T BYTE 3 5R 9 19T changin
412. ments that begins on page 1 310 for more information 2 4 SPL Statements CALL Receiving Input from the Called Procedure The RETURNING clause specifies the procedure variables that receive the returned values from a procedure call If the RETURNING clause is omitted the called procedure must not return any values The following example shows two procedure calls one that expects no values to be returned no_args and one that expects three values to be returned yes_args Three integer variables have been defined to receive the returned values from yes_args CREATE PROCEDURE not_much DEFINE i j k INT CALL no_args 10 20 CALL yes_args 5 RETURNING i j k END PROCEDURE SPL Statements 2 5 CONTINUE CONTINUE Purpose Use the CONTINUE statement to start the next iteration of the innermost FOR WHILE or FOREACH loop Syntax CONTINUE FOR J WHILE wi FOREACH Usage When you encounter a CONTINUE statement the rest of the statements in the innermost loop of the indicated type are skipped Execution continues at the top of the loop with the next iteration In the following example the values 3 through 15 are inserted into the table testtable The values 3 through 9 and 13 through 15 are also returned in the process The value 11 is not returned because the CONTINUE FOR statement is reached and causes the RETURN i WITH RESUME statement to be skipped CREATE PROCEDURE
413. mns of Type INTEGER SMALLINT DECIMAL MONEY FLOAT SMALLFLOAT DECIMAL MONEY FLOAT SMALLFLOAT CHAR NCHAR NVARCHAR VARCHAR DATE INTERVAL DATETIME e Characters must be enclosed in quotation marks Date literals must be formatted in accordance with the DBDATE environment variable When DBDATE is not set the format mm dd yyyy is assumed e For information on using a literal INTERVAL see Literal Interval on page 1 490 e For more information on using a literal DATETIME see Literal DATETIME on page 1 487 The following table indicates the data type requirements for columns that specify the CURRENT DBSERVERNAME SITENAME TODAY or USER functions as the default value Function Name CURRENT DBSERVERNAME SITENAME TODAY USER Data Type Requirements DATETIME column with matching qualifier CHAR NCHAR VARCHAR or NVARCHAR column at least 18 characters long CHAR NCHAR VARCHAR or NVARCHAR column at least 18 characters long DATE column CHAR column at least 8 characters long The next example adds a column to the items table In items the new column item_weight has a literal default value ALTER TABLE items ADD item_weight DECIMAL 6 2 DEFAULT 2 00 BEFORE total_price In this example each existing row in the items table has a default value of 2 00 for the item_weight column Syntax 1 19 ALTER TABLE Using NOT NULL with ADD When you do not indicate a def
414. mp2 would go into tempspc2 and the third one temp3 would go into tempspc3 Temporary tables are created in the directory specified by the DBTEMP envi ronment variable If the DBTEMP environment variable is not set temporary tables are created in the directory of the database that is the dbs directory If you have the Connect privilege on a database you can create temporary tables Once a temporary table is created you can build indexes on the table However you are the only user who can see the temporary table Syntax 1 101 CREATE TABLE Temporary Table Column Definition Temporary Table Column Definition gt column Data Type gt oa a DEFAULT NOT NULL Tomp Table Clause olumn p 1 88 onstraint Definition p 1 103 column is a valid identifier for columns The column name must be 1 102 Syntax unique within a table but you can use the same names in different tables in the same database You define columns for temporary tables in the same manner as you define columns for regular database tables Note that the only difference is the option for defining column constraints which is defined in the following section For more information about defining single columns for temporary tables see Column Definition Option on page 1 87 CREATE TABLE Temporary Table Column Constraint Definition Temp Table Column Constraint Definition p UNIQUE gt
415. mple creates a database that uses a buffered log CREATE DATABASE vehicles WITH BUFFERED LOG If you use a buffered log you marginally enhance the performance of logging at the risk of not being able to re create the last few transactions after a failure See the discussion of buffered logging in Chapter 9 of the Informix Guide to SQL Tutorial Syntax 1 59 CREATE DATABASE An ANSL compliant database does not use buffered logging Designating an ANSI Compliant INFORMIX OnLine Dynamic Server Database The following example creates an ANSI compliant database CREATE DATABASE employees WITH LOG MODE ANSI Creating an ANSI compliant database does not mean that you get ANSI warnings when you run the database You must use the ansi flag or the DBANSIWARN environment variable to receive warnings For additional information about ansi and DBANSIWARN see Chapter 4 in the Informix Guide to SQL Tutorial Logging on INFORMIX SE The following example creates an INFORMIX SE database named accounts with a log file You must use the full pathname to designate the log file CREATE DATABASE accounts WITH LOG IN acct 1992 acct_log If you specify the WITH LOG IN keywords you can use transactions and the statements associated with transactions BEGIN WORK COMMIT WORK and ROLLBACK WORK Conversely if you do not specify the WITH LOG IN keywords you cannot use transactions You can use the START
416. mple shows the EXECUTE IMMEDIATE statement in INFORMIX ESQL C sprintf cdb_text create database s usr_db_id exec sql execute immediate cdb_text References See the EXECUTE FREE and PREPARE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of quick execution in Chapter 5 Syntax 1 191 EXECUTE PROCEDURE EXECUTE PROCEDURE Purpose Use the EXECUTE PROCEDURE statement to execute a procedure from the DB Access interactive editor an SQL API or another stored procedure Syntax PI EEJ EXECUTE PROCEDURE NEE p 1 495 Argument host gos variable Argument Ba parameter name iG Expression p 1 430 SELECT Statement Singleton p 1 310 host variable is a variable defined within the calling program parameter name is the name of the parameter as defined by its CREATE PROCEDURE statement Usage The EXECUTE PROCEDURE statement invokes a procedure called Procedure Name If an EXECUTE PROCEDURE statement has more arguments than are expected by the called procedure an error is returned If an EXECUTE PROCEDURE statement has fewer arguments than are expected by the called procedure the arguments are said to be missing Miss ing arguments are initialized to their corresponding default values if default values were specified See the CREATE PROCEDURE statement on page 1 68 This initialization occurs
417. mplex conditions The following SELECT statements contain examples of complex conditions in their WHERE clauses SELECT customer_num order_date FROM orders WHERE paid_date gt 1 1 92 OR paid_date IS NULL SELECT order_num total_price FROM items WHERE total_price gt 200 00 AND manu_code LIKE H SELECT lname customer_num FROM customer WHERE zipcode BETWEEN 93500 AND 95700 OR state NOT IN CA WA OR The following truth tables show the effect of the AND and OR operators The letter T represents a true condition F represents a false condition and the represents an unknown value Unknown values occur when part of an expression that uses a logical operator is null AND T F fe OR T F T T F T T T T F F F F F T F F T If the Boolean expression evaluates to UNKNOWN the condition is not satisfied Syntax 1 417 Condition 1 418 Syntax Consider the following example within a WHERE clause WHERE ship_charge shi AND order_num 1 p_weight lt 5 023 The row where order_num 1023 is the row where ship_weight is null Because ship_weight is null ship_charge ship_weight is also null there fore the truth value of ship_charge ship_weight lt 5 is UNKNOWN Because order_num 1023 is TRU E the AND table states that the truth value of the entire condition is UNKNOWN Consequently that row is not chosen If the condition used an OR in plac
418. mpty when you issue the ALTER TABLE statement 1 20 Syntax REFERENCES Clause gt REFERENCES Name ALTER TABLE The following rules apply when you place unique or primary key constraints on existing columns When you place a unique or primary key constraint on a column or set of columns and a unique index already exists on that column or set of col umns the constraint shares the index However if the existing index allows duplicates the database server returns an error You must then drop the existing index before adding the constraint When you place a unique or primary key constraint on a column or set of columns and a referential constraint already exists on that column or set of columns the duplicate index is upgraded to unique if possible and the index is shared You cannot have a unique constraint on a BYTE or TEXT column nor can you place referential or check constraints on these types of columns You can place a check constraint on a BYTE or TEXT column However you can check only for IS NULL IS NOT NULL or LENGTH The REFERENCES Clause Table a p 1 506 Lea j ON DELETE CASCADE Use the REFERENCES clause to reference a column or set of columns in another table When you are using the ADD or MODIFY clause you can refer ence a single column When you are using the ADD CONSTRAINT clause you can reference a single column or a set of columns The table ref
419. multiple 1 114S USER function as affected by ANSI compliance 1 2315 1 300S 1 438S syntax in Condition segment 1 405S in expression 1 436S in INSERT 1 250S use in ALTER TABLE 1 188 in CREATE TABLE 1 888 in expression 1 438S 2 63T 2 64T 3 19T in INSERT 1 252S User informix privileges associated with 1 2345 Using correlation names 1 1245 USING DESCRIPTOR keywords information from DESCRIBE 1 164S syntax in EXECUTE 1 1845 in FETCH 1 1945 in OPEN 1 263S in PUT 1 2845 use in FETCH 1 2015 in OPEN 1 269S in PUT 1 1885 1 2885 1 289S USING keyword syntax in EXECUTE 1 186S in OPEN 1 263S use in EXECUTE 1 1868 5 31T in OPEN 1 268S USING SQL DESCRIPTOR keywords in DESCRIBE 1 164S in EXECUTE 1 1875 Utility program chkenv 5 4R crtcmap 5 5R dbexport 5 8R dbimport 5 13R dbload 5 19R 9 28T 10 12T dbschema 5 33R 9 26T oncheck 10 7T 10 12T onload 4 27T 10 11T onstat 10 12T onunload 4 27T 10 11T V VALUE clause after NULL value is fetched 1 215S relation to FETCH 1 214S use in GET DESCRIPTOR 1 212S use in SET DESCRIPTOR 1 355S VALUES clause effect with PUT 1 286S syntax in INSERT 1 245S use in INSERT 1 250S 4 7T VARCHAR data type considerations for UNLOAD statement 1 379S description of 3 22R 9 15T effect on table size 10 14T requirements for LOAD statement 1 257S syntax 1 425S used for performance 10 26T using as default value 1 195 1 895 versus NVARCHAR data type 1 19R with LENGTH function 2
420. n DATETIME 3 9R as delimiter in INTERVAL 3 15R I Icon explanation of Intro 65 IDATA field SET DESCRIPTOR statement 1 357S with X Open programs 1 213S Identifier segment column names 1 4765 column naming allowable characters 1 469S cursor name 1 482S cursor names 1 479S database objects that use 1 469S stored procedures 1 479S syntax 1 469S table names 1 475S 1 477S used in column naming 1 885 using keywords as column names 1 473S variable name 1 4815 IF statement branching 14 22T syntax 2 245 syntax and use 2 245 with null values 2 255 ILENGTH field SET DESCRIPTOR statement 1 357S with X Open programs 1 213S IMMEDIATE keyword in the SET CONSTRAINTS statement 1 349S Implicit connection defined 1 465 with DISCONNECT 1 168S Implicit temporary table 1 100S IN keyword locating BLOB column 10 18T syntax in CREATE AUDIT 1 555 in CREATE DATABASE 1 575 in CREATE TABLE 1 105S in LOCK TABLE 1 260S use in Condition segment 1 408S in Condition subquery 1 414S in CREATE DATABASE 10 5T in CREATE TABLE 10 6T 10 8T with WHERE keyword 1 327S IN keyword used to test for equality in WHERE clause 2 29T IN relational operator 3 33T Index adding for performance 10 21T 13 34T allowable characters in index name 1 469S building with NLS 1 20R clustered 10 25T composite 13 31T creating with CREATE INDEX 1 625 disk space used by 10 16T 10 20T 13 34T displaying information for 1 242S dropping 10 24T dropping
421. n in the WHERE Clause 1 326 Syntax You can use the following kinds of simple conditions or comparisons in the WHERE clause Relational operator condition BETWEEN e IN e ISNULL LIKE or MATCHES You also can use a SELECT statement within the WHERE clause this is called a subquery The following list contains the kinds of subquery WHERE clauses e IN EXISTS ALL ANY SOME Examples of each type of condition are shown in the following sections For more information about each kind of condition see the Condition segment on page 1 404 You cannot use an aggregate function in the WHERE clause unless it is part of a subquery or if the aggregate is on a correlated column originating from a parent query and the WHERE clause is within a subquery that is within a HAVING clause Relational Operator Condition For a complete description of the relational operator condition see page 1 407 A relational operator condition is satisfied when the expressions on either side of the relational operator fulfill the relation set up by the operator The following SELECT statements use the greater than gt and equal relational operators SELECT order_num FROM orders WHERE order_date gt 6 04 93 SELECT fname lname company FROM customer WHERE city 1 3 San SELECT BETWEEN Condition For a complete description of the BETWEEN condition see page 1 408 The BETWEEN condition is satisfied whe
422. n input value that is incompatible with the data type of the column for which it is intended is discovered only when the buffer is flushed When an error is discovered rows in the buffer located after the error are not inserted they are lost from memory The SQLCODE field is set either to an error code or to zero if no error occurs The third element of the sqlerrd array is set to the number of rows that are successfully inserted into the database e Ifa block of rows is successfully inserted into the database SQLCODE is set to zero and sqlerrd to the count of rows e If an error occurs while the FLUSH statement is inserting a block of rows SQLCODE shows which error and sqlerrd contains the number of rows that were successfully inserted Uninserted rows are discarded from the buffer Note When you encounter an SQLCODE error be aware that there may be a corresponding SQLSTATE error value Check the GET DIAGNOSTICS statement for information about getting the SQLSTATE value and using the GET DIAGNOSTICS statement to interpret the SQLSTATE value Counting Total and Pending Rows To count the number of rows actually inserted into the database as well as the number not yet inserted perform the following steps 1 Prepare two integer variables for example total and pending 2 When the cursor opens set both variables to zero 3 Each time a PUT statement executes increment both total and pending 4 Whenever a FLUSH statement exe
423. n the Informix Guide to SQL Tutorial see the discussion of creating and using stored procedures in Chapter 14 Syntax 1 193 FETCH FETCH Purpose Use the FETCH statement to move a cursor to anew row in the active set and to retrieve the row values from memory Syntax data variable RA FETCH cursor id INTO ae cursor variable __ indicator NEXT variable PREVIOUS indicator indicator PRIOR calor variable N FIRST j L data structure J LAST CURRENT NUSING DESCR ET R escriptor A descriptor __ N RELATIVE TOW variable position Y 2 Re sqlda DESCRIPTOR pointer ABSOLUTE ____ ow position cursor id is the identifier of a cursor that was created in an earlier DECLARE statement cursor variable is an embedded variable name that identifies a cursor that was created in an earlier DECLARE statement data structure is a structure which has been declared as a host variable The individual elements of the structure must be matched appropriately to the type of values being fetched data variable is a program variable or host object that receives one value from the fetched row descriptor is a string that identifies the system descriptor area that was allocated with the ALLOCATE DESCRIPTOR statement descriptor is an embedded variable name that identifies the system variable descriptor area that was allocated with the ALLOCATE DESCRIPTOR statemen
424. n the value to the left of the BETWEEN keyword lies in the inclusive range of the two values on the right of the BETWEEN keyword The first two queries in the following example use literal values after the BETWEEN keyword The third query uses the CUR RENT function and a literal interval It looks for dates between the current day and seven days earlier SELECT stock_num manu_code FROM stock WHERE unit_price BETWEEN 125 00 AND 200 00 SELECT DISTINCT customer_num stock_num manu_code FROM orders items WHERE order_date BETWEEN 6 1 92 AND 9 1 92 SELECT FROM cust_calls WHERE call_dtime BETWEEN CURRENT INTERVAL 7 DAY TO DAY AND CURRENT IN Condition For a complete description of the IN condition see page 1 408 The IN condition is satisfied when the expression to the left of the IN keyword is included in the list of values to the right of the keyword The following examples show the IN condition SELECT lname fname company FROM customer WHERE state IN CA WA NJ SELECT FROM cust_calls WHERE user_id NOT IN USER IS NULL Condition For a complete description of the IS NULL condition see page 1 409 Syntax 1 327 SELECT 1 328 Syntax The IS NULL condition is satisfied if the column contains a null value If you use the NOT option the condition is satisfied when the column contains a value that is not null The following example selects the order numbers an
425. n update or delete data using a select cursor as long as it follows the restrictions described on page 1 152 You do not need to use the FOR UPDATE keywords when you declare the cursor DECLARE Insert Cursor An insert cursor increases processing efficiency compared to embedding the INSERT statement directly The insert cursor allows bulk insert data to be buffered in memory and written to disk when the buffer is full This process reduces communication between program and database server and increases the speed of the insertions Cursor Characteristics Structurally you can declare a cursor as a sequential cursor the default condition a scroll cursor using the SCROLL keyword or a hold cursor using the WITH HOLD keywords These structural characteristics are explained in the following sections Sequential Cursor If you use only the CURSOR keyword in a DECLARE statement you create a sequential cursor which can fetch only the next row in sequence from the active set The sequential cursor can read only through the active set once each time it is opened If you are using a sequential cursor on each FETCH the database server returns the contents of the current row and locates the next row in the active set The following INFORMIX ESQL C example creates a sequential cursor exec sql declare s_cur cursor for select fname lname into st_fname st_lname from orders where customer_num 114 Scroll Cursor The SC
426. name you cannot create both private and public synonyms with the same name For example the following code generates an error CREATE SYNONYM our_custs FOR customer CREATE PRIVATE SYNONYM our_custs FOR cust_calls ERROR Synonyms with the Same Name If you own a private synonym and a public synonym exists with the same name and you use a synonym by its unqualified name the private synonym is used If you use DROP SYNONYM with a synonym and multiple synonyms exist with the same name the private synonym is dropped If you issue the DROP SYNONYM statement again the public synonym is dropped Chaining Synonyms with INFORMIX OnLine Dynamic Server 1 82 Syntax If you create a synonym for a table that is not in the current database and the base table for the synonym is dropped the synonym stays in place You can create a new synonym for the dropped table with the name of the dropped table as the synonym name that points to another external or remote table In CREATE SYNONYM this way you can move a table to a new location and chain synonyms together so that the original synonyms remain valid You can chain as many as 16 synonyms in this manner The following steps chain two synonyms together for the customer table which will ultimately reside on the zoo database server Note that the CREATE TABLE statements are not complete 1 In the stores6 database on the database server called training
427. name of a table or synonym Table Table Me RENAME TABLE Name TO Name p 1 506 p 1 506 Synonym Synonym x Namh TO Ware p 1 504 p 1 504 You can rename a table or synonym if any of the following statements are true e You own the table or synonym e You have the DBA privilege on the database e You have the Alter privilege on the table or synonym You cannot change the table owner by renaming the table or synonym You can specify owner as part of old name but an error occurs during compilation if you try to specify owner as part of new name If a view references this table or synonym the text of the view in the sysviews system catalog table is updated to reflect the new table name In an ANSI compliant database you must specify owner if you are referring to a table or synonym that you do not own If you rename a table or synonym that has a trigger it produces the following results The database server replaces the name of the table or synonym in the trigger definition The table or synonym name is not replaced where it appears inside any triggered actions RENAME TABLE The database server returns an error if the new table or synonym name is the same as a correlation name in the REFERENCING clause of the trigger definition When the trigger executes the database server returns an error if it encounters a table or synonym name for which no table or synon
428. nate pair x y y is a numeric expression representing the y coordinate of the rectangular coordinate pair x y COS Function The COS function returns the cosine of a radian expression The following example returns the cosine of the values of the degrees column in the anglestbl table Note that the expression passed to the COS function in this example converts degrees to radians SELECT COS degrees 180 3 1417 FROM anglestbl SIN Function The SIN function returns the sine of a radian expression The following example returns the sine of the values in the radians column of the anglestbl table SELECT SIN radians FROM anglestbl Syntax 1 459 Expression 1 460 Syntax TAN Function The TAN function returns the tangent of a radian expression The following example returns the tangent of the values in the radians column of the anglestbl table SELECT TAN radians FROM anglestbl ACOS Function The ACOS function returns the arc cosine of a numeric expression The following example returns the arc cosine of the value 0 73 in radians SELECT ACOS 0 73 FROM anglestbl ASIN Function The ASIN function returns the arc sine of anumeric expression The following example returns the arc sine of the value 0 73 in radians SELECT ASIN 0 73 FROM anglestbl ATAN Function The ATAN function returns the arc tangent of a numeric expression The following example returns the arc tang
429. nd all the statement blocks that follow the ON EXCEPTION statement The exceptions trapped can be either system or user defined When an exception is trapped the error status is cleared If you specify a variable to receive an ISAM error and no accompanying ISAM error exists a zero returns to the variable If you specify a variable to receive the returned error text and none exists an empty string goes into the variable Placement of the ON EXCEPTION Statement 2 32 SPL Statements The ON EXCEPTION statement is a declarative statement not an executable statement For this reason you must use the ON EXCEPTION statement before any executable statement and after any DEFINE statement in a procedure The following example shows the correct placement of an ON EXCEPTION statement You use ON EXCEPTION statement after the DEFINE statement and before the body of the procedure The following procedure inserts a set of val ues into a table If the table does not exist it is created and the values are inserted The procedure also returns the total number of rows in the table after the insert occurs CREATE PROCEDURE add_salesperson last CHAR 15 first CHAR 15 ETURNING INT EFINE x INT ON EXCEPTION IN 206 If no table was found create one CREATE TABLE emp_list lname CHAR 15 fname CHAR 15 tele CHAR 12 INSERT INTO emp_list VALUES and insert values last first 800 555 1234 END EXCEPTION WITH RESUME INSE
430. ndicates that a sort merge join instead of the nested loop join is to be used on the preceding join table pair It includes a list of the filters that control the sort merge join and where applicable a list of any other join filters For example a join of tables A and B with the filters A cl B clandA c2 lt B c2 lists the first join under Merge Filters and the second join under Other Join Filters When data distributions are not used the INFORMIX SE database server generates fewer query processing statistics than are available from the INFORMIX OnLine Dynamic Server database server As a result estimates for the cost and the number of rows returned may be more precise if you use INFORMIX OnLine Dynamic Server than if you use INFORMIX SE Esti mates returned for queries that include joins tend to be highly inaccurate The following output examples represent what you might see when a SET EXPLAIN ON statement is issued using INFORMIX OnLine Dynamic Server The first two examples contain two entries for a multiple table query and show the SORT SCAN and MERGE JOIN lines Note that in both cases if SORT MERGE was not chosen the second table would have been scanned using an autoindex path An autoindex path is an index constructed automatically at execution time by the engine It is removed when the query completes SET EXPLAIN select i stock_num from items i stock s manufact m where i stock_num s stock_num and i m
431. ne at end of a value for a TEXT value Do not use the backslash character as a field separator It serves as an escape character to inform the LOAD statement that the next character is to be interpreted as part of the data The fields corresponding to character columns can contain more characters than the defined maximum for the field The extra characters are ignored If you are loading files containing VARCHAR or BLOB data types note the following information e Ifyou give the LOAD statement data in which the character including VARCHAR fields are longer than the column size the excess characters are disregarded e You cannot have leading and trailing blanks in BYTE fields e Use the backslash to escape embedded delimiter and backslash characters in all character fields including VARCHAR and TEXT e Data being loaded into a BYTE column must be in ASCII hexadecimal form BYTE columns cannot contain preceding blanks Do not use the following characters as delimiting characters in the LOAD FROM file 0 9 a f A F backslash newline For more information about the format of the input file see the discussion of the dbload utility in the Informix Guide to SQL Reference The following example shows the contents of a hypothetical input file named new_custs 0 Jeffery Padgett Wheel Thrills 3450 El Camino Suite 10 Palo Alto CA 94306 0 Linda Lane Palo Alto Bicycles 2344 University Palo Alto CA 94301 415 323 6440
432. ng for DATETIME value with DBTIME 4 27R specifying for MONEY value with DBMONEY 4 20R FRACTION keyword syntax in DATETIME data type 1 428S in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 14R 1 4915 FREE statement effect on cursors 1 269S freeing prepared statements 5 33T syntax 1 207S with concatenation operator 1 432S FROM keyword alias names 2 79T syntax in PUT 1 2845 in REVOKE 1 300S in SELECT 1 310S use in PUT 1 287S in SELECT 1 323S Function aggregate 2 53T algebraic 1 444S date oriented 2 56T in SELECT statements 2 53T within a stored procedure 14 24T Function expression DBINFO function 1 4485 description of 1 443S in SELECT 1 3145 Functional dependency 8 31T G GET DESCRIPTOR statement syntax 1 210S the COUNT keyword 1 212S use with FETCH statement 1 200S with concatenation operator 1 432S X Open mode 1 2135 GET DIAGNOSTICS statement CLASS_ORIGIN keyword 1 225S CONNECTION_NAME keyword 1 227S exception clause 1 223S MESSAGE_LENGTH keyword 1 225S MESSAGE_TEXT keyword 1 225S MORE keyword 1 222S NUMBER keyword 1 223S purpose 1 2175 RETURNED_SOLSTATE keyword 1 225S ROW_COUNT keyword 1 2235 SERVER_NAME keyword 1 225S statement clause 1 2225 keywords 1 2225 SUBCLASS_ORIGIN keyword 1 225S syntax 1 217S Global transaction 12 21T GOTO keyword in the WHENEVER statement 1 398S GRANT statement automated 11 13T changing grant
433. ng stand for the single character z The following statement retrieves rows from the customer table in which the company column includes the underscore character SELECT FROM customer WHERE company LIKE z_ ESCAPE z You can also use a single character host variable as an escape character The following statement shows the use of a host variable as an escape character EXEC SQL BEGIN DECLARE SECTION char escp z char fname 20 EXEC SQL END DECLARE SECTION EXEC SQL SELECT FNAME FROM customer WHERE company LIKE z_ ESCAPE escp ESCAPE with MATCHES The ESCAPE clause lets you include a question mark an asterisk and a left or right bracket in the quoted string and avoid having them be inter preted as wildcards If you choose to use z as the escape character the char acters z ina string stand for the question mark Similarly the characters z stand for the asterisk Finally the characters zz in the string stand for the single character z The following example retrieves rows from the cus tomer table in which the company column includes the question mark SELECT FROM customer WHERE company LIKE z ESCAPE z Condition Condition with a Subquery Condition with Subquery aN ubquer p 144 a paste ubquer D1 414 ALL ANY SOME Subquer p 1 41 You can use a SELECT statement within a condition this
434. ng the SPACEBAR hh is the number of hours The maximum number of digits allowed is two unless this is the first field and the precision is specified differently by the INTERVAL field qualifier Syntax 1 491 Literal Interval Usage 1 492 Syntax mi is the number of minutes The maximum number of digits allowed is two unless this is the first field and the precision is specified differently by the INTERVAL field qualifier ss is the number of seconds The maximum number of digits allowed is two unless this is the first field and the precision is specified differently by the INTERVAL field qualifier T is the fraction of a second in up to five digits depending on the precision given to the fractional portion in the INTERVAL field qualifier The following examples show literal INTERVAL values INTERVAL 3 6 YEAR TO MONTH INTERVAL 09 55 30 825 HOUR TO FRACTION INTERVAL 40 5 DAY TO HOUR Literal Number Literal Number Purpose Syntax A literal number is an integer or noninteger floating constant The Literal Number segment is used in the following statements and segments GRANT statement INSERT statement UPDATE statement UPDATE STATISTICS statement e Condition segment e Expression segment Usage digit is an integer from 0 to 9 Literal numbers do not contain embedded commas you cannot use a comma to indicate a decimal point You can precede literal numbers
435. ning null values 2 385 syntax 2 388 REVOKE statement column specific privileges 1 303S database level privileges 1 303S granting privileges 11 5T to 11 15T in embedded SQL 5 34T to 5 37T privileges needed 1 301S syntax 1 300S table level privileges 1 301S with a view 11 29T ROLLBACK WORK statement cancels a transaction 4 25T closes cursors 7 18T releases locks 7 8T 7 18T sets SOQLCODE 6 5T syntax 1 306S use with WHENEVER 1 368 1 425 1 3075 with DROP DATABASE 1 173S with DROP INDEX statement 1 175S with DROP PROCEDURE statement 1 176S with DROP SYNONYM statement 1 177S with DROP TABLE statement 1 179S with DROP TRIGGER statement 1 181S with DROP VIEW statement 1 183S ROLLFORWARD DATABASE statement applies log to restored database 4 26T exclusive locking 1 308S syntax 1 308S Root dbspace definition of 10 5T ROOT function syntax in expression 1 444S use in expression 1 446S ROUND function syntax in expression 1 444S use in expression 1 446S Row cost of reading from disk 13 16T defined 2 5T defining 8 20T deleting 1 1595 4 4T description of 1 12T engine response to locked row 1 370S in relational model 1 12T 8 20T inserting 4 6T inserting through a view 1 246S inserting with a cursor 1 248S multi row queries with FETCH 1 195S order guaranteeing independence of 1 117S phantom 1 367S retrieving with FETCH 1 197S rowid definition 1 197S size of fixed length 10 13T updating through a view 1 384S writing buffer
436. nly the data in the systables and when requested the sysdistrib system catalog tables Examining Index Pages The UPDATE STATISTICS statement reads through index pages in order to compute statistics for the query optimizer In addition the statement also looks for pages that have the delete flag marked as one If pages are found 1 394 Syntax UPDATE STATISTICS with the delete flag marked as one the keys so marked are removed from the btree cleaner list This is particularly useful if a system crash causes the btree cleaner list to be lost because it is in shared memory By running the UPDATE STATISTICS statement you can remove those items When to Update Statistics Update the statistics when you perform extensive modifications to a table or when changes are made to tables that are used by one or more procedures and you do not want the database server to reoptimize the procedure at execution time If your application makes many modifications to the data in a particular table update the system catalog table data for that table routinely with the UPDATE STATISTICS statement to improve the efficiency of queries Many is relative to the resolution of the distributions In addition if the data changes do not change the distribution of column values you do not need to execute UPDATE STATISTICS again Specifying the LOW Keyword If you use the LOW keyword or if you specify no keyword the smallest amount of information is
437. no error occurs otherwise it is set to an error code The third element of the sqlerrd array is set to the number of rows that are successfully inserted into the database e Ifa row is put into the insert buffer and buffered rows are not written to the database SQLCODE and sqlerrd both are set to zero SQLCODE because there was no error and sqlerrd because no rows were inserted Ifablock of buffered rows is written to the database during the execution of a PUT statement SOLCODE is set to zero and sqlerrd is set to the number of rows successfully inserted into the database e Ifan error occurs while the buffered rows are written to the database SQLCODE indicates the error and sqlerrd contains the number of success fully inserted rows The uninserted rows are discarded from the buffer Note When you encounter an SQLCODE error be aware that there may be a corresponding SQLSTATE error value Check the GET DIAGNOSTICS statement for information about how to get the SQLSTATE value and how to use the GET DIAGNOSTICS statement to interpret the SQLSTATE value Counting Total and Pending Rows To count the number of rows actually inserted in the database and the number not yet inserted perform the following procedure e Prepare two integer variables for example total and pending When the cursor is opened set both variables to zero 1 290 Syntax PUT e Each time a PUT statement executes increment both total and pending
438. ns Specifying HIGH Distributions If you use the HIGH keyword the constructed distribution is exact rather than statistically significant Because of the time required to gather the infor mation you should use HIGH distributions for specific tables or even col 1 396 Syntax UPDATE STATISTICS umns rather than across the database For very large tables the database server may scan the data once for each column The amount of space desig nated by the DBUPSPACE environment variable determines the number of times the table is scanned For information about DBUPSPACE see Chapter 4 of the Informix Guide to SQL Reference If you do not specify a RESOLUTION clause the default percentage is 0 5 percent Specifying MEDIUM Distributions If you use the MEDIUM keyword the data for the distributions is obtained by sampling Because the data obtained by sampling is usually much smaller than the actual number of rows the time required to construct MEDIUM dis tributions is less than that required for HIGH mode MEDIUM distributions require at least one scan of the table so the creation of MEDIUM distributions executes more slowly than the creation of LOW distributions If you do not specify a RESOLUTION clause the default percentage is 2 5 percent If you do not specify a value for conf the default confidence is 0 95 This can be roughly interpreted as meaning that 95 percent of the time the estimate is equivalent to using HIGH distr
439. ns Exponential and logarithmic functions take at least one argument The return type is FLOAT The following example shows exponential and logarithmic functions Exponential and Logarithmic Functions EXP float expression p gt LOGN float expression LOG10 t float expression float is an expression as defined on page 1 430 whose domain expression is the set of real numbers and range is the set of positive real numbers EXP Function The EXP function returns the exponential value of two numeric expressions You provide a constant and float expression in the form e n e The fol lowing example returns the exponent of 3 for each row of the angles table SELECT EXP 3 FROM angles Syntax 1 451 Expression LOGN Function The LOGN function returns the natural log of a numeric expression The logarithmic value is the inverse of the exponential value The following SELECT statement returns the natural log of population for each row of the history table SELECT LOGN population FROM history WHERE country US ORDER BY date LOG10 Function The LOG10 function returns the log of a value to the base 10 The following example returns the log base 10 of distance for each row of the travel table SELECT LOG10 distance 1 digits FROM travel HEX Function 1 452 Syntax HEX Function EX integer gt H expression gt integer is an expression as
440. ns with SELECT 1 276S statement identifier use 1 274S syntax 1 273S valid statement text 1 275S with concatenation operator 1 4328 Prepared statement describing returned values with DESCRIBE 1 162S executing 1 184S prepared object limit 1 274S valid statement text 1 275S See also PREPARE statement PREVIOUS keyword syntax in FETCH 1 194S use in FETCH 1 196S Primary ke definition of 8 22T Index 33 34 Index restrictions with 8 22T Primary key constraint 1 225 composite 8 23T data type conversion 1 288 defining column as 1 93S definition of 4 19T dropping 1 32S enforcing 1 86S modifying a column with 1 285 referencing 1 22S requirements for 1 205 1 935 rules of use 1 315 1 945 PRIMARY KEY keywords in ALTER TABLE 1 295 in ALTER TABLE statement 1 205 in CREATE TABLE 1 915 1 925 Primary site 12 20T Printing specifying print program with DBPRINT 4 24R PRIOR keyword syntax in FETCH 1 1945 use in FETCH 1 196S Privilege Alter 1 236S 11 8T and views 11 27T to 11 30T ANSI compliant databases 1 12R automating grants of 11 13T column level 11 10T Connect 1 2325 11 6T DBA 1 2335 11 7T default for stored procedures 14 14T default for table using CREATE TABLE 1 85S Delete 1 236S 11 8T 11 28T displaying 4 16T displaying with the INFO statement 1 2425 encoded in system catalog 2 28R 2 32R 11 9T Execute 11 12T 14 14T for triggered action 1 129S granting 11 5T to 11 15T Index 1 236S 11 8T Insert 1 2365 11 8T 11
441. nside a stored procedure if the procedure is called inside a data manipulation statement For example you cannot create a trig ger inside the stored procedure sp_items in the following INSERT statement INSERT INTO items EXECUTE PROCEDURE sp_items See Data Manipulation Statements on page 1 6 for a list of data manipulation statements If you are embedding the CREATE TRIGGER statement in an ESQL C or ESQL COBOL program you cannot use a host variable in the trigger specification You cannot use a stored procedure variable in a CREATE TRIGGER statement You cannot use a ROLLBACK WORK statement to undo a CREATE TRIGGER statement If you roll back a transaction that contains a CREATE TRIGGER statement the trigger remains and you do not receive an error message The Trigger Event The trigger event specifies the type of statement that activates a trigger The trigger event can be an INSERT DELETE or UPDATE statement Each trigger can have only one trigger event The occurrence of the trigger event is the triggering statement Syntax 1 111 CREATE TRIGGER 1 112 Syntax For each table you can define only one trigger that is activated by an INSERT statement and only one trigger that is activated by a DELETE statement For each table you can define multiple triggers that are activated by UPDATE statements See UPDATE Clause on page 1 114 for more information about multiple triggers on the same table You
442. nstraint on a BYTE or TEXT column Locking Implications When you create a referential constraint an exclusive lock is placed on the referenced table The lock is released when the CREATE TABLE statement is done If you are creating a table in a database with transactions and you are using transactions the lock is released at the end of the transaction Using REFERENCES in a Column Definition When you use the REFERENCES option at the column definition level you can reference a single column The following example shows how to create two tables accounts and sub_accounts A referential constraint is created between the foreign key ref_num in the sub_accounts table and the primary key acc_num in the accounts table CREATE TABLE accounts acc_num INTEGER PRIMARY KEY acc_type INTEGER acc_descr CHAR 20 CREATE TABLE sub_accounts sub_acc INTEGER PRIMARY KEY ref_num INTEGER REFERENCES accounts acc_num sub_descr CHAR 20 Note that ref_num is not explicitly called a foreign key in the column definition syntax At the column level the foreign key designation is applied automatically If you are referencing the primary key in another table you do not need to specify the referenced table column In the preceding example you simply can reference the accounts table without specifying a column Because acc_num is the primary key of the accounts table it becomes by default the referenced
443. nt a situation in which you exceed the maximum num ber of locks defined in the INFORMIX OnLine Dynamic Server configuration The maximum number of locks allowed by the INFORMIX SE database server is a characteristic of the particular operating system on which your database server is running e All row and table locks release automatically after a transaction is completed Note that the UNLOCK TABLE statement fails within a database that uses transactions Syntax 1 261 LOCK TABLE The following example shows how to change the locking mode of a table in a database that was created with transaction logging BEGIN WORK LOCK TABLE orders IN EXCLUSIVE MODE COMMIT WORK BEGIN WORK LOCK TABLE orders IN SHARE MODE COMMIT WORK Databases Without Transactions In a database created without transactions table locks set using the LOCK TABLE statement are released after any of the following occurrences An UNLOCK TABLE statement executes The user closes the database The user exits the application To change the lock mode on a table release the lock with the UNLOCK TABLE statement and then issue a new LOCK TABLE statement The following example shows how to change the lock mode of a table in a database that was created without transactions LOCK TABLE orders IN EXCLUSIVE MODE UNLOCK TABLE orders LOCK TABLE orders IN SHARE MODE References See the BEGIN WORK SET ISOLATI
444. ntroduction Chapter Syntax SQL Statements 5 ANSI Compliance and Extensions 7 ALLOCATE DESCRIPTOR 9 ALTER INDEX 12 ALTER TABLE 15 BEGIN WORK 35 CHECK TABLE 37 CLOSE 38 CLOSE DATABASE 41 COMMIT WORK 43 CONNECT 44 CREATE AUDIT 55 CREATE DATABASE 57 CREATE INDEX 62 CREATE PROCEDURE 68 CREATE PROCEDURE FROM 76 CREATE SCHEMA 77 CREATE SYNONYM 80 CREATE TABLE 84 CREATE TRIGGER 110 CREATE VIEW 136 DATABASE 140 DEALLOCATE DESCRIPTOR 143 DECLARE 145 DELETE 159 DESCRIBE 162 DISCONNECT 167 DROP AUDIT 171 DROP DATABASE 172 DROP INDEX 174 DROP PROCEDURE 176 DROP SYNONYM 177 1 2 Syntax DROP TABLE 179 DROP TRIGGER 181 DROP VIEW 183 EXECUTE 184 EXECUTE IMMEDIATE 190 EXECUTE PROCEDURE 192 FETCH 194 FLUSH 204 FREE 207 GET DESCRIPTOR 210 GET DIAGNOSTICS 217 GRANT 231 INFO 241 INSERT 245 LOAD 255 LOCK TABLE 260 OPEN 263 OUTPUT 271 PREPARE 273 PUT 284 RECOVER TABLE 292 RENAME COLUMN 294 RENAME TABLE 296 REPAIR TABLE 299 REVOKE 300 ROLLBACK WORK 306 ROLLFORWARD DATABASE 308 SELECT 310 SET CONNECTION 346 SET CONSTRAINTS 349 SET DEBUG FILE TO 351 SET DESCRIPTOR 353 SET EXPLAIN 360 SET ISOLATION 366 SET LOCK MODE 370 SETLOG 372 SET OPTIMIZATION 374 START DATABASE 376 UNLOAD 378 UNLOCK TABLE 381 UPDATE 383 UPDATE STATISTICS 392 WHENEVER 398 Segments 403 Condition 404 Constraint Name 419 Database Name 421 Data Type 424 DATETIME Field Qualifier 428 Expression 430 Identifier 469 Index
445. num The index in either example is maintained in ascending order which is the default order You also can prevent duplicates in a column or set of columns by creating a unique constraint with the CREATE TABLE or ALTER TABLE statement See the CREATE TABLE or ALTER TABLE syntax for more information CLUSTER Option Use the CLUSTER option to reorder the physical table in the order designated by the index The CREATE CLUSTER INDEX statement fails if a CLUSTER index already exists CREATE CLUSTER INDEX c_clust_ix ON customer zipcode This statement creates an index on the customer table that orders the table physically by zip code You cannot create a CLUSTER index on a table that has an audit trail 1 64 Syntax CREATE INDEX Composite Indexes The following example creates a composite index using the stock_num and manu_code columns of the stock table CREATE UNIQUE INDEX st_man_ix ON stock stock_num manu_code The index prevents any duplicates of a given combination of stock_num and manu_code The index is in ascending order by default You can include up to 16 columns in a composite index The total width of all indexed columns in a single CREATE INDEX statement cannot exceed 255 bytes You can use up to 8 columns in a composite index The total width of all indexed columns in a single CREATE INDEX statement cannot exceed 120 bytes Place columns in the composite index in the order fr
446. o a item number variable Described Item Info Sr LENGTH N PRECISION 7 N scale N NULLABLE 7 N INDICATOR N name 7 N Data KN myPEe 7 N aTa N ILENGTH 7 descriptor is a quoted string that identifies a system descriptor area that is already allocated descriptor is an embedded variable name that identifies a system variable descriptor area that is already allocated field host is the name of a host variable that receives the contents of variable the indicated field of the system descriptor area The field host variable item number item number variable GET DESCRIPTOR host variable must be an appropriate type to receive the value from the system descriptor area is the name of an integer host variable isan unsigned integer that represents one of the values in the system descriptor area is the name of an integer variable that contains an unsigned integer that represents one of the values in the system descriptor area Syntax 1 211 GET DESCRIPTOR Usage If an error occurs during the assignment to any of the identified host variables the contents of the host variable is undefined The role and contents of each of the fields in a system descriptor area are described in SQL API manuals The GET DESCRIPTOR statement can be used in execute procedure statements that have been described with the USING SQL DESCRIPTOR parameter The host variables
447. ode Conventions 10 Introduction Examples of SQL code occur throughout this manual Except where noted the code is not specific to any single Informix application development tool If only SQL statements are listed in the example they are not delineated by semicolons To use this SQL code for a specific product you must apply the syntax rules for that product For example if you are using the Query Lan guage option of DB Access you must delineate multiple statements with semicolons If you are using an SQL API you must use EXEC SQL and a semi colon or other appropriate delimiters at the start and end of each statement respectively For example you might see the following example code CONNECT TO stores6 DELETE FROM customer WHERE customer_num 121 COMMIT WORK DISCONNECT CURRENT For detailed directions on using SQL statements for a particular application development tool or SQL API see the manual for your product Useful On Line Files Also note that dots in the example indicate that more code would be added ina full application but it is not necessary to show it to describe the concept being discussed Useful On Line Files In addition to the Informix set of manuals the following on line files located in the INFORMIXDIR release directory may supplement the information in this manual Documentation describe features not covered in the manual or that Notes have been modified since publication The
448. odesc char tablename 19 intei exec sql begin declare section char demoselect 200 exec sql end declare section This program selects all the columns of a given tablename The tablename is supplied interactively exec sql database stores6 printf This program does a select on a table n printf Enter table name scanf Ss tablename sprintf demoselect select from s tablename exec sql prepare iid from demoselect exec sql describe iid into demodesc Print what describe returns for i 0 i lt demodesc gt sqld i prsqlda demodesc gt sqlvar i Assign the data pointers for i 0 i lt demodesc gt sqld itt switch demodesc gt sqlvar i sqltype amp sqltype case sqlchar demodesc gt sqlvar i sqltype cchartype demodesc gt sqlvar i sqllent demodesc gt sqlvar i sqldata malloc demodesc gt sqlvar i sqllen break Il case sqlsmint case sqlint case sqlserial demodesc gt sqlvar i sqltype cinttype demodesc gt sqlvar i sqldata malloc sizeof int break And so on for each type PREPARE Declare and open cursor for select exec sql prepare d_stmt from demoselect exec sql declare d_curs cursor for d_stmt exec sql open d_curs Fetch selected rows one at a time into demodesc TOT eps thy eed printf n exec sql fetch d_curs using descriptor demodesc if sqlca sql
449. oduct manual The following examples show how to execute prepared statements using system descriptors in INFORMIX ESQL C and INFORMIX ESQL COBOL respectively exec sql execute prep_stmt using sql descriptor descl INFORMIX ESQL C EXEC SQL EXECUTE PREP_STMT USING SQL DESCRIPTOR DESC1 END EXEC INFORMIX ESQL COBOL Syntax 1 187 EXECUTE 1 188 Syntax E C Supplying Parameters Through an sqlda Structure You can specify the sqlda pointer in the USING DESCRIPTOR clause of the EXECUTE statement Each time the EXECUTE statement is run the values described by the sqlda structure are used to replace question mark place holders in the PREPARE statement This method is similar to employing the USING keyword with a list of variables except that your program has full control over the memory location of the data values For more information on the sqlda structure see the manual for the version of INFORMIX ESQL C you are using The following example shows how to execute a prepared statement using an sqlda structure in INFORMIX ESQL C EXEC SQL EXECUTE prep_stmt USING DESCRIPTOR pointer2 Error Conditions with EXECUTE In an ANSI compliant database if you prepare and execute any of the following statements and no rows are returned from the statements the database server returns SQLNOTFOUND 100 INSERT INTO table name SELECT WHERE SELECT INTO TEMP WHERE DELETE WHE
450. of a WHENEVER statement is from the location of the statement in the source module until the next WHENEVER statement with the same excep tion condition SQLERROR SQLWARNING and so on in the same source module If no other WHENEVER statement exists in the source module the statement remains in effect until the end of the program or module WHENEVER The following ESQL C example program has three WHENEVER statements two of which are WHENEVER SQLERROR statements On line 6 the CON TINUE keyword is specified on line 10 STOP is used with SQLERROR Any errors encountered after line 6 and before line 10 are ignored After line 10 and for the rest of the program any SQL errors encountered cause the program to terminate 1 main 2 3 long char_num 4 5 exec sql database test 6 exec sql whenever sqlerror continue 7 printf n nGoing to try first insert n n 8 exec sql insert into test_color values green 9 exec sql whenever not found continue 10 exec sql whenever sqlerror stop 11 printf n nGoing to try second insert n n 12 exec sql insert into test_color values blue 13 exec sql close database 14 printf n nProgram over n n Po i SQLERROR Keyword If you use the SQLERROR keyword any SQL statement that fails is handled as directed by the WHENEVER statement An error occurs when the sqlcode variable is less than zero The specification for the sqlcode variable for each product is listed in the following
451. of sort The following exam ple selects all the rows in the cust_calls table and orders them by call_code and by call_dtime within call_code SELECT FROM cust_calls ORDER BY call_code call_dtime A nested sort Using Select Numbers In place of column names you can enter one or more integers that refer to the position of items in the SELECT clause You can use a select number to order by an expression For example the following example orders by the expres sion paid_date order_date and customer_num using select numbers in a nested sort SELECT order_num customer_num paid_date order_date FROM orders ORDER BY 3 2 Select numbers are required in the ORDER BY clause when SELECT statements are joined by UNION or UNION ALL keywords and compatible columns in the same position have different names Syntax 1 339 SELECT ORDER BY Clause with DECLARE You cannot use a DECLARE statement with a FOR UPDATE clause to associate a cursor with a SELECT statement that has an ORDER BY clause FOR UPDATE Clause 1 340 Syntax Use the FOR UPDATE clause when you prepare a SELECT statement and you intend to update the values returned by the SELECT statement when the val ues are fetched Preparing a SELECT statement that contains a FOR UPDATE clause is equivalent to preparing the SELECT statement without the FOR UPDATE clause and then declaring a FOR UPDATE cursor for the prepared statement The FOR UPDATE keywo
452. og Clause gt WITH LOG IN pathname T p MODE ANSI Elements of a syntax diagram To construct a statement using this diagram start at the top left with the keywords CREATE DATABASE Then follow the diagram to the right pro ceeding through the options that you want The diagram conveys the following information 1 2 3 You must type the words CREATE DATABASE You must supply a database name You can stop taking the direct route to the terminator or you can take one or more of the optional paths If desired you can designate a dbspace by typing the word IN and a dbspace name Introduction 9 How to Use This Manual 5 If desired you can specify logging Here you are constrained by the data base server with which you are working e Ifyou are using INFORMIX OnLine Dynamic Server go to the subdiagram named OL Log Clause Follow the subdiagram by typing the keyword WITH then choosing and typing either LOG BUFFERED LOG or LOG MODE ANSI Then follow the arrow back to the main diagram e If you are using INFORMIX SE go to the subdiagram named SE Log Clause Follow the subdiagram by typing the keywords WITH LOGIN typing a quote supplying a pathname and closing the quotes You can then choose the MODE ANSI option below the line or continue to follow the line across 6 Once you are back at the main diagram you come to the terminator Your CREATE DATABASE statement is complete Example C
453. om most frequently used to least frequently used FILLFACTOR Option Use the FILLFACTOR option to provide for expansion of the index at a later date or to create compacted indexes You provide a percent value ranging from 1 to 100 inclusive The default percent value is 90 When the index is created OnLine initially fills only that percentage of the nodes specified by the FILLFACTOR value If you provide a low percentage value such as 50 you allow room for growth in your index The nodes of the index are initially filled to a certain percentage and contain space for inserts The amount of space available depends on the number of keys in each page as well as the percentage value For example with a 50 percent FILLFACTOR value the page would be half full and could accommodate doubling in growth A low percentage value can result in faster inserts and may be used for indexes that you expect to grow If you provide a high percentage value such as 99 your indexes will be compacted and any new index inserts result in splitting nodes The maxi mum density is achieved with 100 percent With a 100 percent FILLFACTOR value no room is available for growth any additions to the index result in splitting of the nodes A 99 percent FILLFACTOR value allows room for at Syntax 1 65 CREATE INDEX least one insertion per node A high percentage value can result in faster selects and may be used for indexes that you do not expect to grow or for mo
454. omer and orders tables so they precede the column names with the table names SELECT FROM customer orders WHERE customer customer_num orders customer_num SELECT FROM customer c orders o WHERE c customer_num o customer_num Using Subscripts on Character Columns 1 434 Syntax You can use subscripts on CHAR VARCHAR NCHAR NVARCHAR BYTE and TEXT columns The subscripts indicate the starting and ending character positions contained in the expression For example if a value in the Iname column of the customer table is Greenburg the following expression evaluates to burg fname 6 9 Expression Using Rowids You can use the rowid associated with each row of the table as a property of the row The rowid is essentially a hidden column It is unique for each row but it is not necessarily sequential The rowid is sequential and starts at 1 for each table The following examples show possible uses of the ROWID keyword ina SELECT statement SELECT ROWID FROM customer SELECT fname ROWID FROM customer ORDER BY ROWID SELECT HEX rowid FROM customer WHERE customer_num 106 In INFORMIX OnLine Dynamic Server only the last SELECT statement example shows how to get the page number the first six digits after 0x and the slot number the last two digits of the location of your row You cannot use ROWID in the select list of a query that contains an aggregate function Synta
455. on of the Procedure with the WITH RESUME Keyword 2 34 SPL Statements The example on page 2 32 uses the WITH RESUME keyword to indicate that after the statement block in the ON EXCEPTION statement executes execution is to continue atthe LET x SELECT COUNT FROM emp_list state ment which is the line following the line that raised the error For this proce dure this means that the count of salespeople names occurs even if the error occurred ON EXCEPTION Continuation of Procedure Execution After an Exception Occurs If you do not include the WITH RESUME keyword in your ON EXCEPTION statement after an exception is raised the next statement that executes depends on the placement of the ON EXCEPTION statement as described in the following scenarios If the ON EXCEPTION statement is inside a statement block with a BEGIN and an END keyword the execution resumes with the first statement if any after that BEGIN END block That is it resumes after the scope of the ON EXCEPTION statement e If the ON EXCEPTION statement is inside a loop FOR WHILE FOREACH the rest of the loop is skipped and execution resumes with the next itera tion of the loop e Ifthe ON EXCEPTION statement is not contained within any statement or block but only in the procedure the procedure terminates by executing a RETURN statement with no arguments That is the procedure returns a successful status and no values Errors Within
456. on segment 1 405S LIKE 2 37T NOT 2 32T NULL 2 35T OR 2 33T segment 1 500S with WHERE keyword in SELECT 1 326S Relationship attribute 8 15T cardinality 8 9T 8 13T complex 8 28T connectivity 8 8T 8 11T defining in data model 8 8T entity 8 5T existence dependency 8 9T mandatory 8 9T many to many 8 9T 8 11T many to many resolving 8 26T one to many 8 9T 8 11T one to one 8 9T 8 11T optional 8 9T recursive 8 28T redundant 8 29T using matrix to discover 8 10T RELATIVE keyword syntax in FETCH 1 1945 use in FETCH 1 196S Relay Module SQLRM environment variable 4 42R SQLRMDIR environment variable 4 43R Release notes Intro 9R Intro 115S 6T Remote database server 12 8T RENAME COLUMN statement restrictions 1 2945 syntax 1 294S RENAME TABLE statement ANSI compliant naming 1 296S syntax 1 296S REPAIR TABLE statement syntax and use 1 299S Repeatable Read isolation level description of 1 367S 7 12T emulating during update 1 202S REPEATABLE READ keywords syntax in SET ISOLATION 1 366S Replication of data 12 19T Report generator 1 17T Reserved words 1 470S Resolution in UPDATE STATISTICS 1 396S 1 397S with data distributions 1 396S RESOURCE keyword use in GRANT 1 233S use in REVOKE 1 303S Resource manager 12 11T Resource privilege 1 233S 11 7T 13 34T Restricting access using file system 11 4T Result of triggering statement 1 123S RETURN statement exiting a loop 14 23T returning insufficient values 2 385 retur
457. ons The codes indicate the products or conditions that support the path The following codes are used This path is valid only for INFORMIX OnLine Dynamic Server BEJ This path is valid only for INFORMIX SE u gt _ gt NOT 3 i variable How to Use This Manual This path is valid only for DB Access ZE This path is valid for SQL statements in INFORMIX ESQL C and INFORMIX ESQL COBOL ASE This path is valid only for INFORMIX ESQLIC WAS This path is valid only for INFORMIX ESQL COBOL SAS This path is valid only if you are using Informix Stored Procedure Language SPL WE This path is valid only if you have created your data base as an NLS database This path is valid only for INFORMIX OnLine Optical This path is an Informix extension to ANSI standard SQL If you initiate Informix extension checking and include this syntax branch you receive a warning If you have set the DBANSIWARN environment vari able at compile time or have used the ansi compile flag you receive warnings at compile time If you have DBANSIWARN set at run time or if you com piled with the ansi flag warning flags are set in the sqlwarn structure A shaded option is the default Even if you do not explicitly type the option it will be in effect unless you choose another option Syntax enclosed in a pair of arrows indicates that this is a subdiagram The vertical line is a terminator and indicates that the state
458. or 1 238S creating a privilege chain 1 238S database level privileges 1 232S 11 5T default table privileges 1 2375 in 4GL 11 13T in embedded SQL 5 34T to 5 37T passing grant ability 1 237S privileges on a view 1 239S syntax 1 231S table level privileges 1 235S 11 7T use of dbschema 5 34R with CREATE SCHEMA 1 775 GROUP BY clause 1 1255 GROUP BY keywords column number with 3 7T composite index used for 13 31T description of 3 4T indexes for 13 10T 13 34T restrictions in modifiable view 11 24T sorting rows 13 12T syntax in SELECT 1 310S use in SELECT 1 334S H HAVING keyword description of 3 9T syntax in SELECT 1 310S use in SELECT 1 336S Header of a procedure 14 25T HEX function 1 435S syntax in expression 1 452S use in expression 1 4525 HIGH keyword 1 3745 Hold cursor definition of 1 149S 7 18T insert cursor with hold 1 157S use of 1 150S Host machine 12 8T Host variable delimiter for 5 6T description of 5 6T dynamic allocation of 5 33T Index 21 fetching data into 5 21T in DELETE statement 6 4T in INSERT 6 8T in UPDATE 6 14T in WHERE clause 5 14T INTO keyword sets 5 13T null indicator 5 15T restrictions in prepared statement 5 29T truncation signalled 5 12T using non English characters in 1 22R with EXECUTE 5 31T HOUR keyword syntax in DATETIME data type 1 428S in INTERVAL data type 1 485S use as DATETIME field qualifier 3 8R 1 488S as INTERVAL field qualifier 3 14R 1 491S Hyphen as delimiter i
459. or ALTER TABLE statements or on DB Access menus to allow deletes from a parent table to cause deletes on child tables Enhanced CREATE INDEX statement You can now use the FILLFACTOR option on the CREATE INDEX statement to create indexes that provide for expansion of the index at a later time or to create compacted indexes Enhanced Arithmetic Functions You can now use certain trigonometric and algebraic functions in your SQL statements The new functions include ABS MOD POW ROOT SQRT COS SIN TAN ACOS ASIN ATAN ATAN2 EXP LOGN and LOG10 Introduction 15 New Features in Informix Version 6 0 Products That Use SQL 16 Introduction Enhanced Error Handling You can now use a new statement to retrieve standard and multiple diagnostic information about your SQL statements The GET DIAGNOS TICS statement is compliant with X Open and ANSI ISO specifications and provides a standard method for detecting and handling error mes sages The GET DIAGNOSTICS statement is used with a new error handling status variable called SQLSTATE New DBINFO Function The DBINFO function allows you to find the following information o The dbspace name for a given table o The last serial value inserted into a table o The number of rows processed by SELECT INSERT DELETE UPDATE and EXECUTE PROCEDURE statements New Environment Variables The following Informix environment variables and X Open categories described in Chapter 4 of the Info
460. or the table The default size is eight pages next pages is the length in pages for the subsequent extents The default size is eight pages See Chapter 10 of the Informix Guide to SQL Tutorial about calculating extent sizes The minimum size of an extent is four pages If you specify an extent size or next extent size smaller than the minimum size the database server returns an error Syntax 1 107 CREATE TABLE The following example specifies a first extent of 20 pages and allows the rest of the extents to use the default size CREATE TABLE emp_info f_name CHAR 20 l_name CHAR 20 position CHAR 20 start_date DATETIME YEAR TO DAY comments VARCHAR 255 EXTENT SIZE 20 Revising Extent Sizes for Unloaded Tables You can revise the CREATE TABLE statements in generated schema files to revise the extent and next extent sizes of unloaded tables See the INFOR MIX OnLine Dynamic Server Administrator s Guide for information about revising extent sizes LOCK MODE Clause 1 108 Syntax LOCK MODE Clause LOCK MODE gt ROW The default locking granularity is a page Row level locking provides the highest level of concurrency However if you are using many rows at one time the lock management overhead can become significant You can also exceed the maximum number of locks available depending on the configuration of your INFORMIX OnLine Dynamic Server system Pa
461. osite table in which each pair of rows one from each table satisfying the join condition is linked to form a single row You can create two table joins multiple table joins and self joins Syntax 1 331 SELECT The following diagram shows the syntax for a join Join lt column me atonia column gt N 7 name pri 500 N a 7 name able able NI Name NJ Name L A p 1 506 p 1 506 N alias N alias A View View N Name A N Name A p 1 510 p 1 510 Synonym Synonym N Name L 7 Pham Pee p 1 504 p 1 504 alias is the alias assigned in the FROM clause 1 332 Syntax column name is the name of a column in one of the tables Two Table Joins The following example shows a two table join SELECT order_num lname fname FROM customer orders WHERE customer customer_num orders customer_num Note You do not have to select the column on which the two tables are joined Multiple Table Joins A multiple table join is a join of more than two tables Its structure is similar to the structure of a two table join except that you have a join condition for more than one pair of tables in the WHERE clause When columns from dif ferent tables have the same name you must distinguish them by preceding the name with its associated table or table alias as in table column See Table Name on page 1 506 for the full syntax of a
462. ot use rowid as a column name Performing the following actions causes an error Creating a table or view with a column named rowid e Altering a table by adding a column named rowid Renaming a column to rowid Identifier The following example uses the term rowid table name CREATE TABLE rowid column INTEGER date DATE char CHAR 20 Using Keywords as Table Names The examples in this section show workarounds that involve owner naming when you use the keyword STATISTICS or OUTER as a table name This also applies to the use of STATISTICS or OUTER as a view name or synonym Using statistics as a table name causes the following example to fail because the database server interprets it as part of the UPDATE STATISTICS syntax rather than as a table name in an UPDATE statement UPDATE statistics SET mycol 10 The workaround in the following example specifies an owner name with the table name to avoid ambiguity UPDATE josh statistics SET mycol 10 Using outer as a table name causes the following example to fail because the database server interprets outer as a keyword for performing an outer join SELECT mycol FROM outer fails The workaround in the following example uses owner naming to avoid ambiguity SELECT mycol FROM josh outer Syntax 1 475 Identifier Workarounds That Use the Keyword AS In some cases although a statement is not ambiguous and the syntax
463. ou to perform updates that are not possible with just the UPDATE statement because both the decision to update and the values of the new data items can be based on the original contents of the row The UPDATE statement cannot interrogate the table being updated Syntax that is Incompatible with the FOR UPDATE Clause A SELECT statement that uses a FOR UPDATE clause must conform to the following restrictions e You can select data from only one table e The statement cannot include any aggregate functions AVG COUNT MAX MIN or SUM The statement cannot include any of the following clauses or keywords DISTINCT INTO TEMP UNION GROUP BY ORDER BY UNIQUE For a description of how to declare a FOR UPDATE cursor for a SELECT statement that does not include a FOR UPDATE clause see page 1 152 INTO TEMP Clause INTO TEMP Clause gt INTO TEMP temp table name X T gt WITH NO LOG temp table name is the simple name of a table You cannot use any of the extended syntax described in the Table Name segment on Syntax 1 341 SELECT 1 342 Syntax page 1 506 You are limited to the conventions described in the Identifier segment on page 1 469 The INTO TEMP clause creates a temporary table that contains the query results The initial and next extents for the temp table are always eight pages Temporary tables created with the INTO TEMP clause are explicit temporary tables Explicit temporary tables
464. ound exists to using null as a variable name and attempting to use it in an IN condition Using ON OFF or PROCEDURE with TRACE If you define a procedure variable called on off or procedure and you attempt to use it in a TRACE statement the value of the variable does not trace Instead the TRACE ON TRACE OFF or TRACE PROCEDURE statements execute You can trace the value of the variable by making the variable into a more complex expression The following example shows the ambiguous syntax and the workaround DEFINE on off procedure INT TRACE on ambiguous TRACE 0 on ok TRACE off ambiguous TRACE off ok TRACE procedure ambiguous TRACE O0 procedure ok Using GLOBAL as a Variable Name If you attempt to define a variable with the name global the define operation fails The syntax shown in the following example conflicts with the syntax for defining global variables and no workaround exists DEFINE global INT fails Syntax 1 481 Identifier Using EXECUTE SELECT or WITH as Cursor Names Do not use an EXECUTE SELECT or WITH keyword as the name of a cursor If you try to use one of these keywords as the name of a cursor in a FOREACH statement the cursor name is interpreted as a keyword in the FOREACH statement No workaround exists The following example does not work DEFINE execute INT FOREACH execute FOR SELECT coll error looks like FOREACH EXECUTE P
465. ow control 14 22T receiving data from SELECT 1 318S recursion 14 24T REFERENCES clause 14 18T returning values 14 25T revoking privileges on 1 3015 14 16T security purposes 11 3T simulating errors 2 365 tracing triggered actions 15 12T use 14 3T variable 14 16T Stored Procedure Language See SPL stores6 database call_type table columns A 5R catalog table columns A 4R copying Intro 10R Intro 135S 8T creating Intro 10R Intro 135S 8T customer table columns A 2R cust_calls table columns A 5R data values A 15R description of A 1R items table columns A 3R manufact table columns A 5R map of A 6R orders table columns A 3R overview Intro 9R Intro 12S 7T primary foreign key relationships A 8R to A 15R state table columns A 6R stock table columns A 4R structure of tables A 2R Structured Query Language See SQL Subquery beginning with ALL ANY SOME keywords 1 330S beginning with EXISTS keyword 1 330S beginning with IN keyword 1 329S correlated 1 4135 3 32T 4 22T 13 32T definition of 1 326S in Condition segment 1 413S in DELETE statement 4 6T in SELECT 3 32T to 3 42T in UPDATE SET 4 13T in UPDATE WHERE 4 12T performance of 13 32T restrictions with UNION operator 1 344S with DISTINCT keyword 1 313S See also Condition segment Subscripting in a WHERE clause 2 44T on character columns 1 4345 SPL variables 14 18T Subservient table 3 21T Substring 2 27T 14 18T SUM function as aggregate function 2 53T synta
466. ow the Database Server Stores Rows The database server must retain all the rows in the active set for a scroll cursor until the cursor closes because it cannot be sure which row the program asks for next When a scroll cursor opens the database server implements the active set as a temporary table although it may not fill this table immediately The first time a row is fetched the database server copies it into the temporary table as well as returning it to the program When a row is fetched for the second time it can be taken from the temporary table This scheme uses the fewest resources in case the program abandons the query before it fetches all the rows Rows that are never fetched are usually not created or are saved in a temporary table Syntax 1 197 FETCH Specifying Where Values Go in Memory Each value from the select list of the query or the output of the executed procedure must be returned into a memory location You can specify these destinations in one of the following ways Using the INTO clause of a SELECT statement Using the INTO clause of a EXECUTE PROCEDURE statement Using the INTO clause of a FETCH statement U sing a system descriptor E C e Using an sqlda structure Using the INTO Clause of SELECT The SELECT statement that is associated with the cursor can contain an INTO clause that specifies which program variables are to receive the values You can use this method only when the SELECT
467. owing example contains a view and an INSERT statement that achieve this effect CREATE VIEW salary_view AS SELECT lname fname current_salary FROM salary WHERE entered_by USER INSERT INTO salary VALUES Smith Pat 75000 USER Syntax 1 247 INSERT Inserting Rows with a Cursor If you associate a cursor with an INSERT statement you must use the OPEN PUT and CLOSE statements to carry out the INSERT operation For databases that have transactions but are not ANSI compliant you must issue these statements within a transaction If you are using a cursor associated with an INSERT statement the rows are buffered before they are written to the disk The insert buffer is flushed under the following conditions e The buffer becomes full e A FLUSH statement executes A CLOSE statement closes the cursor e Ina database that is not ANSI compliant an OPEN statement implicitly closes and then reopens the cursor e A COMMIT WORK statement ends the transaction When the insert buffer is flushed the front end processor performs appropriate data conversion before it sends the rows to the database server When the database server receives the buffer it begins to insert the rows one at a time into the database If an error is encountered while the database server inserts the buffered rows into the database any buffered rows following the last successfully inserted rows are discarded Inserting Rows into a Database Wi
468. owing section Condition Constraint Name Database Name e Data Type DATETIME Field Qualifier e Expression Identifier Index Name INTERVAL Field Qualifier Literal DATETIME Literal INTERVAL Literal Number Procedure Name Quoted String Relational Operator e Synonym Name e Table Name e View Name Syntax 1 403 Condition Condition Purpose Syntax Usage 1 404 Syntax Use a Condition segment to test data to determine whether it meets certain qualifications You can use the Condition segment in the following ways In an ALTER TABLE or CREATE TABLE statement as a check constraint In a DELETE statement within the WHERE clause In a SELECT statement within the WHERE clause and the HAVING clause In an UPDATE statement within the WHERE clause In an IF statement if you are using SPL In a WHILE statement if you are using SPL T Comparison g Ti Condition p 1 405 Condition with Subquery p 1 413 A condition is a collection of one or more search conditions optionally connected by the logical operators AND or OR Search conditions fall into the following categories Comparison conditions also called filters or Boolean expressions Conditions with a subquery Condition Restrictions on a Condition A condition can only contain an aggregate function if it is used in the HAVING clause of a SELECT statement or the HAV
469. pace 10 10T row access 13 16T seek time 13 17T sequential access 13 17T 13 34T sorting replaces nonsequential access 13 37T splitting tall tables 10 29T splitting wide tables 10 28T time costs of query 13 14T use of derived data 10 30T use of redundant data 10 31T using CHAR instead of NCHAR 1 19R Performance analysis 80 20 rule 13 7T measurement 13 6T methods 13 27T to 13 41T nonsequential access 13 37T to 13 41T optimizing techniques 13 4T setting up test environment 13 28T timing from 4GL program 13 6T from command script 13 6T from watch 13 6T using query plan 13 29T verifying problem 13 4T Permission with SYSTEM 2 40S Phantom row 1 367S PIPE keyword in the OUTPUT statement 1 2725 Pipe symbol See concatenation operator Pipes unnamed 12 7T Plus sign arithmetic operator 1 4315 Populating tables 9 27T POW function syntax in expression 1 444S use in expression 1 4465 Precedence rules for environment variables 4 7R PRECISION field setting with SET DESCRIPTOR 1 3585 with GET DESCRIPTOR 1 2145 PREPARE statement description of 5 29T error return in SQLERRD 5 12T executing 1 184S increasing performance efficiency 1 283S missing WHERE signalled 5 10T multiple SQL statements 5 30T multi statement text 1 2775S 1 2815S parameterizing a statement 1 2785 parameterizing for SQL identifiers 1 279S preparing GRANT 11 13T question mark as placeholder 1 273S releasing resources with FREE 1 208S restrictio
470. ped table The old synonym then refers to the new object See the CREATE SYNONYM statement for a complete discussion of synonym chaining You cannot use a ROLLBACK WORK statement to undo a DROP SYNONYM statement If you roll back a transaction that contains a DROP SYNONYM statement the synonym is not re created and you do not receive an error message Syntax 1 177 DROP SYNONYM Reference See the CREATE SYNONYM statement in this manual In the Informix Guide to SQL Tutorial see the discussion of synonyms in Chapter 12 1 178 Syntax DROP TABLE DROP TABLE Purpose Syntax Usage Use the DROP TABLE statement to remove a table along with its associated indexes and data Table Ha DROP TABLE _ _Name cf p 1 506 Synonym Name p 1 504 You must be the owner of the table or have DBA status to use the DROP TABLE statement Use the DROP TABLE statement with caution When you remove a table you also delete the data stored in it the indexes or constraints on the columns including all the referential constraints placed on its columns any local synonyms assigned to it any triggers created for it and any authorizations you have granted on the table You also drop all views based on the table You do not remove any synonyms for the table that have been created in an external database You cannot drop any of the system catalog tables You cannot drop a table that is not in the
471. plemented either as an ascending index that allows only unique entries or an ascending index that allows duplicates When one of these constraints is placed on a column the database server performs the following functions Creates a unique index for a unique or primary key constraint Creates an index that is not unique for the columns specified in thereferential constraint However if a constraint was already created on the same column or set of columns an index is not built Instead the index is shared by the constraints If the existing index is not unique it is upgraded if a unique or primary key constraint is placed on that column CREATE TABLE Because these constraints are enforced through indexes you cannot create an index using the CREATE INDEX statement for a column that is of the same type as the constraint placed on that column For example if a unique con straint exists on a column you can create neither an ascending unique index for that column nor a duplicate ascending index Constraint Names A row is added to the sysindexes system catalog table for each new primary key unique or referential constraint that does not share an index with an existing constraint The index name in the sysindexes system catalog table is created with the following format space lt tabid gt _ lt constraint id gt In this format tabid and constraint id are from the systables and sysconstraints system catalog tables respect
472. program variables have changed since the previous OPEN statement reopening the cursor can generate an entirely different active set Even if the values of the variables are unchanged if data in the table was modified since the previous OPEN statement the rows in the active set can be different Reopening an Procedure Cursor The values named in the USING clause are evaluated only when the cursor is opened While the cursor is open subsequent changes to program variables in the USING clause do not change the active set of returned rows The active set remains constant until a subsequent OPEN statement closes the cursor and reopens it or until the program closes the open cursor which releases the active set Reopening the cursor creates a new active set based on the current values of the variables If the program variables have changed since the previous OPEN statement reopening the cursor can generate an entirely different active set Even if the values of the variables are unchanged if the procedure takes a dif ferent execution path from the previous OPEN statement the rows in the active set can be different Reopening an Insert Cursor When you reopen an insert cursor that is already open you effectively flush the insert buffer any rows stored in the INSERT buffer are written into the database table The database server first closes the cursor which accounts for the flush and then reopens the cursor See the discussion of the PUT st
473. prompt_for_y_or_n another new customer Y exec sql close ins_curs Naming Program Variables in PUT When the INSERT statement is prepared see the PREPARE statement on page 1 273 you cannot use program variables in its VALUES clause However you can represent values using a question mark placeholder You supply the missing values by listing the names of program variables in the FROM clause of the PUT statement The following INFORMIX ESQL C example lists host variables in a PUT statement exec sql begin declare section char ins_comp 80 char sel2 80 char u_company 20 char answer 1 y exec sql end declare section main exec sql database stores6 exec sql prepare ins_comp from Syntax 1 287 PUT insert into customer customer_num company exec sql declare ins_curs cursor for sel2 exec sql open ins_curs while 1 printf nEnter a customer gets u_company exec sql put ins_curs from u_company printf Enter another customer y n if answer getch y break exec sql close ins_curs values 0 Listing host variables in a PUT statement in an INFORMIX ESQLIC program Using a System Descriptor Area 1 288 Syntax You can create a system descriptor area that describes the data type and memory location of one or more values You can then specify that system descriptor area in the USING SQL DESCRIPTOR clause of the PUT statem
474. ps an implicit connection as shown in the following example that implicit connection cannot be re established DATABASE stores6 mydbsrvr DISCONNECT CURRENT DATABASE stores6 mydbsrvr error no connection See The Implicit Connection with DATABASE Statements on page 1 46 for more information about an implicit connection DISCONNECT Use the keyword DEFAULT to terminate an explicit default connection a connection made using the CONNECT TO DEFAULT statement or an implicit connection if one exists You establish an implicit connection in your program when you execute one of the DATABASE statements DATABASE START DATABASE and so on prior to issuing a CONNECT statement If the statement does not specify a server as shown in the following example the connection is made to the default server EXEC SQL DATABASE stores6 DISCONNECT DEFAULT If the statement specifies a database server as shown in the following example an implicit connection is made to that server EXEC SQL DATABASE stores6 mydbsrvr DISCONNECT DEFAULT See The DEFAULT Option on page 1 46 and The Implicit Connection with DATABASE Statements on page 1 46 for more information about the default database server and implicit connections Use the keyword ALL to terminate all connections established by the appli cation up to that time For example the following DISCONNECT statement disconnects the current connection a
475. r SELECT order_date ship_date FROM orders ORDER BY order_date In the following query the order_date column is selected implicitly by the SELECT so you can use order_date in the ORDER BY clause SELECT FROM orders ORDER BY order_date Ordering by a Derived Column You can order by a derived column by supplying a display label in the SELECT clause as shown in the following example SELECT paid_date ship_date span customer_num FROM orders ORDER BY span Ascending and Descending Orders You can use the ASC and DESC keywords to specify ascending smallest value first or descending largest value first order The default order is ascending 1 338 Syntax SELECT For DATE and DATETIME data types smallest means earliest in time and largest means latest in time For standard character data types the ASCII collating sequence is used See page 1 502 for a listing of the collating sequence NLS For the NLS data types NCHAR and NVARCHAR the native collation sequence is used Nulls in the ORDER BY Clause Null values are ordered as less than values that are not null Using the ASC order the null value comes before the non null value using DESC order the null value comes last Nested Ordering If you list more than one column in the ORDER BY clause your query is ordered by a nested sort The first level of sort is based on the first column the second column determines the second level
476. r The data type of each variable must be compatible with the corresponding value required by the prepared statement The variable name can include an indicator variable provided its use is appropriate at the corresponding point in the prepared statement The following example executes the prepared UPDATE statement in INFORMIX ESQL C strcopy stml update orders set order_date where po_num exec sql prepare statement_1 from stml exec sql execute statement_1l using order_date ord_ind po_num EXECUTE Supplying Parameters through a System Descriptor You can create a system descriptor area that describes the data type and memory location of one or more values and then specify the descriptor in the USING SQL DESCRIPTOR clause of the EXECUTE statement Each time that the EXECUTE statement is run the values described by thesystem descriptor area are used to replace question mark placeholders in the PREPARE statement This method is similar to using the USING key word with a list of variables except that your program has full control over the memory location of the data values The COUNT field corresponds to the number of dynamic parameters in the prepared statement The value of COUNT must be less than or equal to the value of the occurrences specified when the system descriptor area was allocated with the ALLOCATE DESCRIPTOR statement For more information on system descriptors see your INFORMIX ESOL pr
477. r the column fname as post fname If the trigger event is an UPDATE statement you can define both old and new correlation names to refer to column values before and after the triggering update See Using Correlation Names in Triggered Actions on page 1 124 for the rules governing the use of correlation names You can use the UPDATE REFERENCING clause only if you define a FOR EACH ROW triggered action CREATE TRIGGER Action Clause Referencing Action Clause Referencing Triggered one ee now x Triggered p t nike Triggered BEFORE 4 Acton List AFTER Action List p 1 121 p 1 121 If the CREATE TRIGGER statement contains an INSERT REFERENCING a DELETE REFERENCING or an UPDATE REFERENCING clause you must include a FOR EACH ROW triggered action list in the action clause You can also include BEFORE and AFTER triggered action lists but they are optional See Action Clause on page 1 116 for information on the BEFORE FOR EACH ROW and AFTER triggered action lists Triggered Action List Triggered Acton List J INSERT Statement p 1 245 Condition p 1 404 WHEN 4 DELETE j Statement p 1 159 UPDATE KJ Statement L4 p 1 383 PROCEDURE p 1 192 a The triggered action consists of an optional WHEN condition and the action statements Objects that are referenced in the triggered a
478. r cursor with hold for select customer_num from customer where city Pittsburgh exec sql open c_master if SQLCODE 0 the open worked exec sql fetch c_master into p_custnum discover first customer while SQLCODE 0 while no errors and not end of pittsburgh customers exec sql begin work start transaction for customer p_custnum exec sql open c_detail using p_custnum if SQLCODE 0 detail open succeeded exec sql fetch c_detail into p_orddate get first order while SQLCODE 0 while no errors and not end of orders exec sql update orders set order_date 08 15 90 where current of c_detail if status 0 update was ok exec sql fetch c_detail into p_orddate next order if SQLCODE SQLNOTFOUND correctly updated all found orders exec sql commit work make updates permanent set status else some failure in an update save_status SQLCODE save error for loop control exec sql rollback work SQLCODE save_status force loop to end if SQLCODE 0 all updates and the commit worked ok exec sql fetch c_master into p_custnum next customer exec sql close c_master To close a hold cursor use either the CLOSE statement to close the cursor explicitly or the CLOSE DATABASE or DISCONNECT statements to close it implicitly CLOSE DATABASE closes all cursors Syntax 1 151 DECLARE Declaring
479. r example if the new correlation name is post you refer to the new value for the column fname as post fname CREATE TRIGGER If the trigger event is an INSERT statement using the old correlation name as a qualifier causes an error because no value exists before the row is inserted See Using Correlation Names in Triggered Actions on page 1 124 for the rules governing the use of correlation names You can use the INSERT REFERENCING clause only if you define a FOR EACH ROW triggered action DELETE REFERENCING Clause DELETE REFERENCING Clause e REFERENCING OLD ow va AS correlation name is a name you assign to an old column value so that you can reference it within the triggered actions The old col umn value in the triggering table is its value before the triggering statement executes Once you assign a correla tion name you can use it only inside the FOR EACH ROW triggered action See Action Clause Referencing on page 1 121 The correlation name follows the same syn tax rules as other identifiers See Identifier on page 1 469 The correlation name must be unique within the CREATE TRIGGER statement correlation name p You use the correlation name to refer to an old column value by preceding the column name with the correlation name and a period For example if the old correlation name is pre you refer to the old value for the column fname as pre fname If th
480. r particular release to ensure that your Informix product is properly set up before you begin to work with it A matrix depicting possible client server configurations is included in the Installation Guide Depending on the database server you are using you or your system administrator need either the INFORMIX SE Administrator s Guide or the INFORMIX OnLine Dynamic Server Administrator s Guide and INFORMIX OnLine Dynamic Server Archive and Backup Guide The DB Access User Manual describes how to invoke the utility to access modify and retrieve information from Informix database servers When errors occur you can look them up by number and learn their cause and solution in the Informix Error Messages manual If you prefer you can look up the error messages in the on line message file described in the sec tion ASCII and PostScript Error Message Files later in this Introduction How to Use This Manual How to Use This Manual This manual assumes that you are using INFORMIX OnLine Dynamic Server as your database server Features and behavior specific to INFORMIX SE are noted throughout the manual The following sections describe the conventions used in this manual for typographical format syntax and example of code Typographical Conventions Informix product manuals use a standard set of conventions to introduce new terms illustrate screen displays describe command syntax and so forth The following typographical con
481. r that can yield true for x is the IS NULL operator That is x IS NULL is true and x IS NOT NULL is not true If an expression within the condition has an UNKNOWN value due to the use of an uninitialized variable it is an immediate error The statement terminates and an exception is raised SPL Statements 2 25 IF 2 26 SPL Statements IF Statement List C BEGIN Statement gt Block p 1 72 CALL Statement p 2 3 END CONTINUE Statement p 2 6 EXIT Statement p 2 14 FOR Statement p 2 16 FOREACH Statement p 2 20 IF Statement p 2 24 LET Statement p 2 28 RAISE EXCEPTION Statement p 2 36 a ee EE RETURN Statement p 2 38 SYSTEM Statement p 2 40 TRACE Statement p 2 42 PFiifi ff i fie ff WHILE Statement p 2 46 ep 9 2 io a T 3 D a LTT IF Subset of SOL Statements Allowed in an IF Statement You can use any SQL statement in the statement block except for the ones in the following list ALLOCATE DESCRIPTOR CHECK TABLE CLOSE DATABASE CONNECT CREATE DATABASE CREATE PROCEDURE DATABASE DEALLOCATE DESCRIPTOR DECLARE DESCRIBE DISCONNECT EXECUTE EXECUTE IMMEDIATE FETCH FLUSH FREE GET DESCRIPTOR GET DIAGNOSTICS INFO LOAD OPEN OUTPUT PREPARE PUT REPAIR TABLE ROLLFORWARD DATABASE SET CONNECTION SET DESCRIPTOR START DATAB
482. ransaction is locked and remains locked throughout the transaction A trans action that contains many such statements or that contains statements affect ing many rows can exceed the limits placed by your operating system or INFORMIX OnLine Dynamic Server configuration on the maximum number of simultaneous locks If no other user is accessing the table you can avoid locking limits and reduce locking overhead by locking the table with the LOCK TABLE statement after you begin the transaction As with all locks this table lock is released when the transaction terminates You can issue the BEGIN WORK statement only if a transaction is not in progress If you issue a BEGIN WORK statement while you are in a transaction the database server returns an error Syntax 1 35 BEGIN WORK If you use the BEGIN WORK statement within a routine called by a WHENEVER statement specify WHENEVER SQLERROR CONTINUE and WHENEVER SQLWARNING CONTINUE before the ROLLBACK WORK state ment This prevents the program from looping if the ROLLBACK WORK statement encounters an error or a warning With ANSI Compliant Databases The BEGIN WORK statement is not needed because transactions are implicit A warning is generated if you use a BEGIN WORK statement immediately following one of these statements DATABASE COMMIT WORK CREATE DATABASE ROLLBACK WORK START DATABASE An error is generated if you use a BEGIN WORK statement after any other statement Referen
483. ration overrul ing your instruction to wait and returns an error code In the case of either a suspected or an actual deadlock the database server returns an error Cautiously use the unlimited waiting period created when you specify the WAIT option without seconds If you do not specify an upper limit and the process that placed the lock somehow fails to release it suspended processes could wait indefinitely Because a true deadlock situation does not exist the database server does not take corrective action In a networked environment the DBA establishes a default value for seconds using the onconfig parameter DEADLOCK_TIMEOUT If you use a SET LOCK MODE statement to set an upper limit your value applies only when your waiting period is shorter than the system default The number of seconds that the process waits applies only if you acquire locks within the current server and a remote server within the same transaction References See the LOCK TABLE UNLOCK TABLE and SET ISOLATION MODE in this manual In the Informix Guide to SQL Tutorial see the discussion of SET LOCK MODE in Chapter 7 Syntax 1 371 SET LOG SET LOG Purpose Syntax Usage 1 372 Syntax Use the SET LOG statement to change your INFORMIX OnLine Dynamic Server database logging mode from buffered transaction logging to unbuffered transaction logging or vice versa SET a T LOG BUFFERED You activate transaction logging when you create a d
484. rd notifies the database server that updating is possible causing it to use more stringent locking than it would with a select cursor You cannot modify data through a cursor without this clause You can specify particular columns that can be updated After you declare a cursor for a SELECT FOR UPDATE statement you can update or delete the currently selected row using an UPDATE or DELETE statement with the WHERE CURRENT OF clause The words CURRENT OF refer to the row that was most recently fetched they replace the usual test expressions in the WHERE clause Your program might contain statements such as the sequence of statements shown in the following example to update rows with a particular value EXEC SQL BEGIN DECLARE SECTION char fname 16 char lname 16 EXEC SQL END DECLARE SECTION EXEC SQL connect to stores6 select statement being prepared contains a for update clause EXEC SQL prepare x from select fname lname from customer for update EXEC SQL declare xc cursor for x note no for update clause in prepare for 77 SELECT EXEC SQL fetch xc into fname lname if strncemp SQLSTATE 00 2 0 break printf Sd s s n cnum fname lname if cnum 999 update rows with 999 customer_num EXEC SQL update customer set fname rosey where current of xc EXEC SQL close xc EXEC SQL disconnect current A SELECT FOR UPDATE like an update cursor allows y
485. rder_num FROM items WHERE stock_num 1 Syntax 1 329 SELECT 1 330 Syntax EXISTS Subquery For a complete description of the EXISTS subquery see page 1 414 With the EXISTS subquery one or more columns can be returned The following example of a SELECT statement with an EXISTS subquery returns the stock number and manufacturer code for every item that has never been ordered and is therefore not listed in the items table It is appro priate to use an EXISTS subquery in this SELECT statement because you need the correlated subquery to test both stock_num and manu_code in items SELECT stock_num manu_code FROM stock WHERE NOT EXISTS SELECT stock_num manu_code FROM items WHERE stock stock_num items stock_num AND stock manu_code items manu_code The preceding example would work equally well if you use a SELECT in the subquery in place of the column names because you are testing for the existence of a row or rows ALL ANY SOME Subquery For a complete description of the ALL ANY SOME subquery see page 1 415 In the following example the SELECT statements return the order number of all orders that contain an item whose total price is greater than the total price of every item in order number 1023 The first SELECT statement uses the ALL subquery and the second SELECT statement produces the same result by using the MAX aggregate function SELECT DISTINCT order_num FROM items WHERE total_price
486. rds in your INFO statement to display a list of tables information about the columns of a table or information about the indexes of a table Syntax 1 241 INFO Use the TABLES keyword to display a list of the tables in the current database The name of a table can appear in one of the following ways e If you are the owner of the cust_calls table it appears as cust_calls e If you are not the owner of the cust_calls table the table name is preceded by the owner s name as in june cust_calls Use the COLUMNS FOR keywords to display the names and data types of the columns in a specified table and whether null values are allowed The follow ing examples show an INFO statement and the resulting display of information about the columns in a table INFO COLUMNS FOR cust_calls Column name Type Nulls customer_num INTEGER no call_dtime DATETIME YEAR TO MINUTE yes user_id CHAR 18 yes call_code CHAR 1 yes call_descr CHAR 240 yes res_dtime DATETIME YEAR TO MINUTE yes res_descr CHAR 240 yes Use the INDEXES FOR keyword to display the name owner and type of each index ina specified table whether the index is clustered and the names of the columns that are indexed The following examples show an INFO statement and the resulting display of information about the indexes of a table INFO INDEXES FOR cust_calls Index name Owner Type Cluster Columns c_num_dt_ix velma unique No customer_nu
487. red by the locale where the software is run New Features in Informix Version 6 0 Products That Use SQL The user can o Create or access database information in any language available on the system by changing a few environment variables o Name user defined objects such as databases tables columns views cursors and files using a foreign character set o Use the new NCHAR and NVARCHAR data types in place of CHAR and VARCHAR respectively for storing national characters In addition by installing one or more language supplements with an Informix product the user can view error and warning messages in the language of the locale Enhanced Database Connections You can now use three new statements CONNECT DISCONNECT and SET CONNECTION to provide a connection oriented association between client and server processes in a networked or a non networked environment These three statements are compliant with X Open and ANSI ISO specifi cations Applications with embedded SQL can use these statements for more uniform and portable syntax when accessing local or remote data Cascading Deletes Support for cascading deletes is provided in INFORMIX OnLine Dynamic Server as an enhancement to referential integrity Previously when you attempted to delete a row from a parent table without deleting rows from associated child tables first the delete was disallowed Now you can specify the ON DELETE CASCADE option on either the CREATE TABLE
488. ref_type did not exactly correspond to the values for acc_num and acc_type in an existing row in the accounts table the database server returns an error Likewise if you attempt to update sub_accounts with values for ref_num and ref_type that do not correspond to an equivalent set of values in acc_num and acc_type from the accounts table the database server returns an error If you are referencing a primary key in another table you do not have to state the primary key columns in that table explicitly Referenced tables that do not specify the columns to be referenced default to the primary key columns The references section of the previous example can be rewritten as shown in the following example FOREIGN KEY ref_num ref_type REFERENCES accounts Because acc_num and acc_type is the primary key of the accounts table and no other columns are specified the foreign key ref_num and ref_type references those columns Syntax 1 95 CREATE TABLE 1 96 Syntax Data Type Restrictions The data types of the referencing and referenced columns must be identical unless the column is of type SERIAL You can specify SERIAL for the primary key of the parent table and INTEGER for the foreign key In the previous example a one to one correspondence exists between the data types of the primary and foreign keys If the primary key column is defined as type SERIAL the statement is successfully executed You cannot place a referential co
489. res6 database is in the stockdata dbspace but you want the customer data to be in a separate dbspace called custdata use the following statements CRI CRI EATE DATABASE stores6 IN stockdata EATE TABLE customer customer_num SERIAL 101 fname CHAR ELS iname CHAR 15 company CHAR 20 addressl CHAR 20 address2 CHAR 20 city CHAR 15 state CHAR 2 zipcode CHAR 5 phone CHAR 18 IN custdata EXTENT SIZE 16 Isolating a table in a separate dbspace If your table has one or more blob columns you can store the blob data with the table data or in a separate blobspace See the Data Type segment on page 1 424 for more information The following example shows how blobspaces and dbspaces are specified CREATE TABLE The following statement creates the resume table The data for the table is stored in the employ dbspace The data in the resume column is stored with the table but the data associated with the photo column is stored in a blobspace named photo_space CREATE TABLE resume fname CHAR 15 lname CHAR 15 phone CHAR 18 recd_date DATETIME YEAR TO HOUR contact_date DATETIME YEAR TO HOUR comments VARCHAR 250 100 resume TEXT IN TABLE photo BYTE IN photo_space IN employ Extent Option Extent Option p p us first ae oa next Ej EXTENT SIZE NEXT SIZE pag pages es first pages is the length in pages of the first extent f
490. riable 1 480S NULL relational operator 2 35T NULL value testing in BYTE expression 3 5R testing with TEXT data type 3 21R Null value checking for in SELECT 1 1845 1 318S defined 8 23T detecting in ESQL 5 15T in INSERT statement 4 7T in SPL IF statement 2 255 inserting with the VALUES clause 1 252S restrictions in primary key 8 22T returned implicitly by stored procedure 2 38S specifying as default value 1 205 testing for 2 35T updating a column 1 387S used in Condition with NOT operator 1 405S used in the ORDER BY clause 1 339S with logical operator 2 36T with SPL WHILE statement 2 465 NUMERIC data type See DECIMAL data type NVARCHAR data type description of 3 18R 9 15T syntax 1 425S versus VARCHAR data type 1 19R O OF keyword syntax in DECLARE 1 145S use in DECLARE 1 153S OLD keyword in DELETE REFERENCING clause 1 119S in INSERT REFERENCING clause 1 119S in UPDATE REFERENCING clause 1 120S ON DELETE CASCADE keyword DELETE trigger event 1 1125 ON EXCEPTION statement placement of 2 325 scope of control 14 29T syntax 2 318 trapping errors 14 27T user generated errors 14 30T ON keyword syntax in CREATE INDEX 1 635 in GRANT 1 231S in REVOKE 1 300S use in CREATE INDEX 1 645 in GRANT 1 237S ON Archive utility using the ARC_DEFAULT environment variable 4 14R ON Archive utility using the ARC_KEYPAD environment variable 4 15R oncheck utility 10 7T 10 12T 13 31T ONCONFIG environment variable 4 39R oncon
491. ries to access a locked row or table SET LOCK MODE TO WAIT S seconds NOT WAIT seconds is the maximum number of seconds that a process waits for a lock to release You can direct the response of the database server in the following ways when a process tries to access a locked row or table NOT WAIT ends the operation immediately and returns an error code This is the default condition WAIT suspends the process until the lock releases WAIT seconds suspends the process until the lock releases or until the end of a waiting period specified in seconds If the lock remains after waiting it ends the operation and returns an error code INFORMIX SE does not support the seconds option If you decide that a process should wait for a lock to release you cannot limit the waiting period The SET LOCK MODE option is available on machines that use kernel lock ing To determine whether your machine uses kernel locking inspect the directory that holds the database files If the directory contains files with the extension lok your system does not use kernel locking and the SET LOCK MODE option is unavailable SET LOCK MODE WAIT Keyword The database server protects against the possibility of a deadlock when you request the WAIT option Before suspending a process the database server checks whether suspending the process could create a deadlock If the data base server discovers a deadlock could occur it ends the ope
492. riggered SQL statement is also UPDATE and the columns in both statements including any nontriggering columns in the triggering UPDATE are mutually exclusive For example if the following UPDATE statement which updates columns a and b of tab1 is the triggering statement UPDATE tabl SET a b a 1 b 1 The first UPDATE statement in the following example is a valid triggered action but the second one is not because it updates column b again UPDATE tabl SET c c UPDATE tabl SET b 1 OK 1 ILLEGAL e The triggered SQL statement is a SELECT statement The SELECT statement can be a triggered statement in the following instances o The SELECT statement appears in a subquery in the WHEN clause or a triggered action statement o The triggered action is a stored procedure and the SELECT statement appears inside the stored procedure This rule which states that a triggered SQL statement cannot reference the triggering table with the two noted exceptions applies recursively to all cas cading triggers which are considered part of the initial trigger This means that a cascading trigger cannot update any columns in the triggering table that were updated by the original triggering statement including any non triggering columns affected by that statement For example assume the following UPDATE statement is the triggering statement UPDATE tabl SET a b a 1 b 1 Syntax 1 127
493. rmix Guide to SQL Reference are new in Version 6 0 ARC_DEFAULT ARC_KEYPAD COLLCHAR DBAPICODE DBNLS DBSPACETEMP DBUPSPACE ENVIGNORE INFORMIXC INFORMIXSERVER INFORMIXSHMBASE INFORMIXSTACKSIZE LANG LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME oOo 0 0 0 0 0 0 oO oO oOo oO oO oO oO oO Oo 8 New Features in Informix Version 6 0 Products That Use SQL e New Data Distribution Features You can use the UPDATE STATISTICS statement to create data distributions for each table The database server uses these data distribu tions to improve the choice of execution paths for SELECT statements The new data distribution feature affects application development in the following three ways o The syntax for the UPDATE STATISTICS statement has been expanded o Anew environment variable DBUPSPACE sets the upper limit of disk space that you want to use when columns are sorted o You can use the dbschema utility to print distribution information e Introduction of Environment Configuration Files The following environment configuration files can contain default values of environment variables o INFORMIXDIR etc informix rc o informix These optional files allow the administrator or the user to set environment variables in much the same way a login or profile file is used so that the variables do not need to be set at each session Introduction 17 New Features in Informix Version 6 0 Products That Use SQL 18 I
494. rmix Guide to SQL Tutorial see the discussions of database design in Chapter 8 and implementing the data model in Chapter 9 DEALLOCATE DESCRIPTOR DEALLOCATE DESCRIPTOR Purpose Syntax Usage E C Use the DEALLOCATE DESCRIPTOR statement to free a system descriptor area that was previously allocated for a specified descriptor or descriptor variable AN DEALLOCATE DESCRIPTOR descriptor q descriptor Ke variable descriptor is a string that identifies the system descriptor area that is allocated with the ALLOCATE DESCRIPTOR statement descriptor is an embedded variable name that identifies the system variable descriptor area that is allocated with the ALLOCATE DESCRIPTOR statement The DEALLOCATE DESCRIPTOR statement frees all the memory associated with the system descriptor area identified by descriptor or descriptor variable All the value descriptors including memory for data value in the value descriptors are also freed A descriptor or descriptor variable can be reused after it is deallocated Deallocation occurs automatically at the end of the program Deallocating a nonexistent descriptor or descriptor variable results in an error You cannot use the DEALLOCATE DESCRIPTOR statement to deallocate an sqlda structure You can use it only to free the memory allocated for a system descriptor area Syntax 1 143 DEALLOCATE DESCRIPTOR The following examples show the DEALLOCATE DESCRIPTOR statement for
495. rocedure within a procedure You can however drop another procedure Subset of SOL Statements Allowed in the Statement Block You can use any SQL statement in the Statement Block except those listed in Figure 1 2 Figure 1 2 CHECK TABLE FREE CLOSE GET DESCRIPTOR CLOSE DATABASE INFO CONNECT LOAD CREATE DATABASE OPEN CREATE PROCEDURE OUTPUT CREATE PROCEDURE FROM PREPARE DATABASE PUT DECLARE REPAIR DESCRIBE ROLLFORWARD DATABASE EXECUTE SET DESCRIPTOR EXECUTE IMMEDIATE START DATABASE FETCH UNLOAD FLUSH WHENEVER SQL statements that cannot be used in a stored procedure You can use a SELECT statement in only two cases e You can use the INTO TEMP clause to put the results of the SELECT statement into a temporary table e You can use the SELECT INTO form of the SELECT statement to put the resulting values into procedure variables Syntax 1 73 CREATE PROCEDURE Figure 1 3 1 74 Syntax Restrictions on a Procedure Called in a Data Manipulation Statement If a stored procedure is called as part of an INSERT UPDATE DELETE or SELECT statement the called procedure cannot execute any of the statements listed in Figure 1 3 This ensures that changes cannot be made that affect the SQL statement that contains the procedure call ALTER INDEX DROP SYNONYM ALTER OPTICAL DROP TABLE ALTER TABLE DROP TRIGGER BEGIN WORK DROP VIEW COMMIT WORK INSERT CREATE TABLE RENAME COLUMN CREATE TRIGGER RENAME TABL
496. rom mytab fails The following example repeats the AS keyword SELECT mycol AS as from mytab Using from as a column label causes the following example to fail because the database server expects a table name to follow the first from SELECT mycol from FROM mytab fails The following example uses the AS keyword to identify the first from as a column label SELECT mycol AS from FROM mytab Using AS with Table Aliases The examples in this section show workarounds use the AS keyword with a table alias The first pair shows how to use the ORDER FOR GROUP HAVING INTO UNION WITH CREATE GRANT or WHERE keyword as a table alias Using order as a table alias causes the following example to fail because the database server interprets order as part of an ORDER BY clause SELECT FROM mytab order fails The workaround in the following example uses the keyword AS to identify order as a table alias SELECT FROM mytab AS order The following two examples show how to use the keyword WITH as a table alias Syntax 1 477 Identifier 1 478 Syntax Using with as a table alias causes the following example to fail because the database server interprets the keyword as part of the WITH CHECK OPTION syntax select from mytab with fails The workaround in the following example uses the keyword AS to identify with as a table alias exec sql select from mytab
497. row and you are not using a cur sor In this case the INTO clause must be in the first SELECT statement You can put the results of a UNION operator into a temporary table by putting an INTO TEMP clause in the final SELECT statement Duplicate Rows in a Combined SELECT 1 344 Syntax If you use the UNION operator alone the duplicate rows are removed from the complete set of rows That is if multiple rows contain identical values in each column only one row is retained If you use the UNION ALL operator all the selected rows are returned the duplicates are not removed The following example uses the UNION ALL operator to join two SELECT SELECT statements without removing duplicates The query returns a list of all the calls that were received during the first quarter of 1992 and the first quarter of 1993 SELECT customer_num call_code FROM cust_calls WHERE call_dtime BETWEEN DATETIME 1992 1 1 YEAR TO DAY AND DATETIME 1992 3 31 YEAR TO DAY UNION ALL SELECT customer_num call_code FROM cust_calls WHERE call_dtime BETWEEN DATETIME 1993 1 1 YEAR TO DAY AND DATETIME 1993 3 31 YEAR TO DAY If you want to remove duplicates use the UNION operator without the keyword ALL in the query In the preceding example if the combination 101 B were returned in both SELECT statements a UNION operator would cause the combination to be listed once If you want to remove duplicates within each SELE
498. rsor and EXECUTE all other prepared statements statements Preparing Statements with SQL Identifiers You cannot use question mark placeholders for SQL identifiers such as a table name or a column name you must specify these identifiers in the statement text when you prepare it However if these identifiers are not available when you write the statement you can construct a statement that receives SQL identifiers from user input The following INFORMIX ESQL C program example prompts the user for the name of a table and uses that name in a SELECT statement Because the table name is unknown until run time the number and data types of the table col umns also are unknown Therefore the program cannot allocate host vari ables to receive data from each row in advance Instead this program fragment describes the statement into an sqlda descriptor and fetches each row using the descriptor The fetch puts each row into memory locations dynamically provided by the program Syntax 1 279 PREPARE 1 280 Syntax If a program retrieves all rows in the active set the FETCH statement would be placed in a loop that fetched each row If the FETCH statement retrieves more than one data value column another loop exists after the FETCH which performs some action on each data value include lt stdio h gt exec sql include sqlca exec sql include sqlda exec sql include sqltypes char malloc main struct sqlda dem
499. rsor through its statement identifier The following INFORMIX ESQL C example illustrates the use of an insert cursor The code includes the following statements The DECLARE statement associates a cursor called ins_curs with an INSERT statement that inserts data into the customer table The VALUES clause names a data structure called cust_rec the ESQL C preprocessor PUT converts cust_rec to a list of values one for each component of the structure The OPEN statement creates a buffer e A function not defined in the example obtains customer information from an interactive user and leaves it in cust_rec The PUT statement composes a row from the current contents of the cust_rec structure and sends it to the row buffer The CLOSE statement inserts into the customer table any rows that remain in the row buffer and closes the insert cursor int keep_going 1 exec sql begin declare section struct cust_row fields of a row of customer table cust_rec exec sql end declare section exec sql declare ins_curs cursor for insert into customer values cust_rec exec sql open ins_curs for sqlca sqlcode 0 amp amp keep_going keep_going get_user_input cust_rec ask user for new customer if keep_going user did supply customer info cust_rec customer_num 0 request new serial value exec sql put ins_curs if sqlca sqlcode 0 no error from PUT keep_going
500. rt to the data type of the corresponding column The following table indicates how your Informix product expects you to represent the data types in the LOAD file Type of Data Input Format blank One or more blank characters between delimiters You can include leading blanks in fields that do not correspond to character columns date A character string in the following format month day year You must state the month as a two digit number You can use a two digit number for the year if the year is in the 20th century The value must be an actual date for example February 30 is illegal You can specify a different date format with the DBDATE and LC_TIME environment variables See Chapter 4 of the Informix Guide to SQL Reference for more information about environment variables MONEY A value that can have leading currency symbols NULL Nothing between the delimiters time A character string in the following format year month day hour minute second fraction You cannot use type specification or qualifiers for DATETIME or INTERVAL values The year must be a four digit number and the month a two digit number Types of data and their input format for a LOAD statement If you include any of the following special characters as part of the value of a field you must precede the character with a backslash Backslash Delimiter 1 256 Syntax LOAD New line anywhere in the value of a VARCHAR or NVARCHAR column e New li
501. rted values are constants the PUT statement has a special effect Instead of creating a row and putting it in the buffer the PUT statement merely increments a counter When you use a FLUSH or CLOSE statement to empty the buffer one row and a repetition count are sent to the database server which inserts that number of rows In the following INFORMIX ESQL C example 99 empty customer records are inserted into the customer table Because all values are constants no disk out put occurs until the cursor closes The constant zero for customer_num causes generation of a SERIAL value int count exec sql declare fill_c cursor for insert into customer customer_num values 0 exec sql open fill_c for count 1 count lt 99 count exec sql put fill_c exec sql close fill_c Inserting empty customer records into a table in an INFORMIX ESQLIC program Naming Program Variables in INSERT 1 286 Syntax When the INSERT statement is written as part of the cursor declaration in the DECLARE statement you can name program variables in the VALUES clause When each PUT statement is executed the contents of the program variables at that time are used to compose the row that is inserted into the buffer Note You can name only program variables in the VALUES clause when the INSERT statement is written as part of the DECLARE statement Variable names are not rec ognized in the context of a prepared statement which is associated with a cu
502. s You must have Resource privilege to take advantage of the Index priv ilege Any user with the Connect privilege can create an index on temporary tables provides the ability to add or delete columns modify column data types or add or delete constraints provides all privileges The PRIVILEGES keyword is optional The following example grants the Delete and Select privileges on all columns and the Update privilege on customer_num fname and Iname for the cus tomer table to users mary and john GRANT DELETE SELECT UPDATE customer_num fname lname ON customer TO mary john GRANT To grant these table level privileges to all authorized users use the keyword PUBLIC as shown in the following example GRANT DELETE SELECT UPDATE customer_num fname lname ON customer TO PUBLIC Restricting Privileges at the Table Level You must take action to restrict privileges at the table level The database server automatically grants to PUBLIC all table level privileges except Alter and References when you create a table To limit table access you must revoke all privileges and regrant only those you want as shown in the following example REVOKE ALL ON customer FROM PUBLIC GRANT ALL ON customer TO john mary GRANT SELECT fname lname company city ON customer TO PUBLIC In an ANSI compliant database only the table owner receives privileges when a table is created
503. s escape character with LIKE 1 410S as escape character with MATCHES 1 411S Backup See Archive BEFORE keyword 1 116S BEGIN WORK statement locking in a transaction 1 35S specifies start of a transaction 4 24T syntax 1 358 BETWEEN keyword syntax in Condition segment 1 405S use in Condition segment 1 408S in SELECT 1 327S BETWEEN keyword used to test for equality in WHERE clause 2 29T BETWEEN operator 2 32T Binary Large Object BLOB choosing location for 10 18T disk storage for 10 4T 10 6T effect of isolation on retrieval 1 3685 estimating disk space for 10 17T in a LOAD statement 1 257S in an UNLOAD statement 1 379S See also BYTE data type See also TEXT data type blobspace 10 4T 10 18T BLOB See Binary Large Object Boolean expression and logical operator 2 36T in Condition segment 1 404S Bourne shell how to set environment variables 4 5R profile file 4 4R BUFFERED keyword syntax in SET LOG 1 372S BUFFERED LOG keywords syntax in CREATE DATABASE 1 57S use in CREATE DATABASE 1 598 Buffered logging 1 575 9 22T Building your data model 8 3T to 8 33T BYTE data type choosing location for 10 18T considerations for UNLOAD statement 1 379S description of 3 5R 9 19T disk storage for 10 4T estimating disk space for 10 17T inserting data 3 5R requirements for LOAD statement 1 257S restrictions in Boolean expression 3 5R with GROUP BY 3 5R with LIKE or MATCHES 3 5R with ORDER BY 3 5R restrictions with GROUP BY 3 7
504. s expressions see Literal Number as an Expression on page 1 439 e The TODAY function in an expression see TODAY Function on page 1 439 The CURRENT function in an expression see CURRENT Function on page 1 440 e Literal DATETIME as an expression see Literal DATETIME as an Expres sion on page 1 441 e Literal INTERVAL as an expression see Literal INTERVAL as an Expres sion on page 1 441 e The UNITS keyword in an expression see UNITS Keyword on page 1 442 Syntax 1 437 Expression Quoted String as an Expression The following examples show quoted strings as expressions SELECT The first name is fname FROM customer INSERT INTO manufact VALUES SPS SuperSport UPDATE cust_calls SET res_dtime 1992 1 1 10 45 WHERE customer_num 120 AND call_code B USER Function The USER function returns a string containing the login name of the current user that is the person running the process The following statements show how you might use the USER function INSERT INTO cust_calls VALUES 221 CURRENT USER B Decimal point off NULL NULL SELECT FROM cust_calls WHERE user_id USER UPDATE cust_calls SET user_id USER WHERE customer_num 220 The USER function does not change the case of a user id If you use USER in an expression and the present user is Robertm the USER function returns Robertm not robertm If
505. s on a view or the All privilege because All includes Index References and Alter For views that reference only tables in the current database if the owner of a view loses the Select privilege on any of the tables underlying the view the view is dropped For detailed information refer to the CREATE TABLE statement which also describes creating views References 1 240 Syntax See the CREATE TABLE and REVOKE statements in this manual In the Informix Guide to SQL Tutorial see the discussions of database and table level privileges in Chapter 4 and privileges and security in Chapter 11 INFO INFO Purpose Syntax Usage Use the INFO statement to display a variety of information about databases and tables INFO TABLES Tabl ms COLUMNS POR Name p 1 506 2B INDEXES ACCESS PRIVILEGES REFERENCES STATUS The following types of information can be displayed by issuing the INFO statement The names of the tables in the current database e Column information for a specified table e Index information for a specified table e Access privileges for a specified table References privileges for the columns of a specified table e Status information for a specified table Instead of using the SOL statement INFO you can use the Info options on the SQL menu or TABLE menu to display the same and additional information Displaying Tables Columns and Indexes You can use keywo
506. s returned by the CURRENT function If the last qualifier specifies a smaller field that is less significant than what exists in the expression the new fields are filled in with constant values A missing MONTH or DAY field is filled in with 1 and the missing HOUR to FRACTION fields are filled in with 0 In the following example the first EXTEND call evaluates to the call_dtime column value of YEAR TO SECOND The second statement expands a literal DATETIME so that an interval can be subtracted from it You must use the EXTEND function with a DATETIME value if you want to add it to or subtract it from an INTERVAL value that does not have all the same qualifiers The third example updates only a portion of the datetime value the hour posi tion The EXTEND function yields just the hh mm part of the datetime Sub tracting 11 00 from the hours minutes of the datetime yields an INTERVAL value of the difference plus or minus and subtracting that from the original value forces the value to 11 00 EXTEND call_dtime YEAR TO SECOND EXTEND DATETIME 1989 8 1 YEAR TO DAY YEAR TO MINUTE INTERVAL 720 MINUTE 3 TO MINUTE UPDATE cust_calls SET call_dtime call_dtime EXTEND call_dtime HOUR TO MINUTE DATETIME 11 00 HOUR TO MINUTE WHERE customer_num 106 Syntax 1 457 Expression MDY Function The MDY function returns a type DATE value with three expressions that evaluate to integers representing the
507. s the most expensive item that is in stock but has not been ordered SELECT MAX unit_price FROM stock WHERE NOT EXISTS SELECT FROM items WHERE stock stock_num items stock_num AND stock manu_code items manu_code Nulls are ignored unless every value in the specified column is null If every column value is null the MAX keyword returns a null for that column MIN Keyword 1 464 Syntax The MIN keyword returns the lowest value in the column or expression Using the DISTINCT keyword does not change the results The following example finds the least expensive item in the stock table SELECT MIN unit_price FROM stock Nulls are ignored unless every value in the specified column is null If every column value is null the MIN keyword returns a null for that column Expression SUM Keyword The SUM keyword returns the sum of all the values in the specified column or expression as shown in the following example If you use the DISTINCT keyword the sum is for only distinct values in the column or expression SELECT SUM total_price FROM items WHERE order_num 1013 Nulls are ignored unless every value in the specified column is null If every column value is null the SUM keyword returns a null for that column You cannot use the SUM keyword with a character column COUNT DISTINCT and UNIQUE Keywords The COUNT DISTINCT and UNIQUE keywords return the number of unique values in the column or expres
508. s well as all dormant connections DISCONNECT ALL If you disconnect a specific connection using connection name or conn_nm variable you receive an error if the specified connection is not a current or dormant connection A DISCONNECT statement that does not terminate the current connection does not change the context of the current environment Syntax 1 169 DISCONNECT If a transaction is active the DISCONNECT statement returns an error The transaction remains active and the application must explicitly commit it or roll it back If an application terminates without issuing a DISCONNECT state ment because of a system crash or program error for example active transactions are rolled back You cannot use the PREPARE statement for the DISCONNECT statement References 1 170 Syntax See the CONNECT SET CONNECTION and DATABASE statements in this manual DROP AUDIT DROP AUDIT Purpose Use the DROP AUDIT statement to delete an audit trail file Syntax Table Name S DROP AUDIT FOR p 1 506 Synonym Name p 1 504 Usage When you finish making a backup of your database files use the DROP AUDIT statement to remove the old audit trail file Use the CREATE AUDIT statement to start anew audit trail for a table You must own the table or have the DBA privilege to use the DROP AUDIT statement The following example assumes that you have just backed up the stores6 database It remov
509. sage FOREACH A FOREACH loop is the procedural equivalent of using a cursor When a FOREACH statement executes the database server takes the following actions 1 2 A cursor is declared and opened implicitly The first row is obtained from the query contained within the FOREACH loop or the first set of values is obtained from the called procedure Each variable in the variable list is assigned the value of the corresponding value from the active set created by the SELECT statement or the called procedure The statement block is executed The next row is fetched from the SELECT statement or called procedure on each iteration step 3 is repeated The loop terminates when no more rows are found that satisfy the SELECT statement or called procedure The implicit cursor is closed when the loop terminates Because the statement block can contain additional FOREACH statements cursors can be nested No limit exists to the number of cursors that can be nested A procedure that returns more than one row or set of values is called a cursory procedure SPL Statements 2 21 FOREACH The following procedure illustrates the three types of FOREACH statements with a SELECT INTO clause with an explicitly named cursor and with a procedure call CREATE PROC FOREACH INS END FOR FOREACH IF END END FOR FOREACH INS END FOR END PROCEDU EDURE foreach_ex DEFINE i j INT SELECT cl
510. scripting 2 44T WHERE CURRENT OF clause impact on trigger 1 1125 WHERE CURRENT OF keywords syntax in DELETE 1 159S in UPDATE 1 383S use in DELETE 6 7T in UPDATE 1 390S 6 15T WHERE keyword Boolean expression in 2 36T comparison condition 2 29T to 2 45T date oriented functions in 2 60T enforcing data constraints 11 27T host variables in 5 14T in DELETE 4 4T to 4 6T joining tables 1 331S null data tests 2 35T prevents use of index 13 32T 13 33T 13 35T range of values 2 32T relational operators 2 29T selecting rows 2 28T setting descriptions of items 1 354S subqueries in 3 33T syntax in DELETE 1 159S Index 49 50 Index in SELECT 1 310S in UPDATE 1 383S testing a subscript 2 44T use in DELETE 1 160S in UPDATE 1 388S with a subquery 1 326S with ALL keyword 1 330S with ANY keyword 1 330S with BETWEEN keyword 1 327S with IN keyword 1 327S with IS keyword 1 3275 with LIKE keyword 1 328S with MATCHES keyword 1 3285 with NOT keyword 2 32T with OR keyword 2 33T with relational operator 1 3265 with SOME keyword 1 330S wildcard comparisons 2 37T See also Condition segment WHILE keyword in CONTINUE statement 2 68 in EXIT 2 148 WHILE statement looping in a stored procedure 14 23T syntax 2 468 with NULL expressions 2 465 Wildcard character asterisk 2 12T Wildcard characters with LIKE or MATCHES 1 498S Wildcard comparison in WHERE clause 2 37T to 2 44T WITH APPEND keywords in the SET DEBUG FILE TO statement 1 35
511. se a COMMIT or ROLLBACK statement in your transaction You cannot explicitly defer the NOT NULL constraint for a column NOT NULL constraints are not named or set of columns However if you defer checking a primary key constraint the checking of the NOT NULL constraint for that column or set of columns is also deferred To defer the checking of all NOT NULL constraints you must defer all constraints Syntax 1 349 SET CONSTRAINTS References See the CREATE TABLE statement in this manual See Chapter 4 of the Informix Guide to SQL Tutorial for additional information about constraints 1 350 Syntax SET DEBUG FILE TO SET DEBUG FILE TO Purpose Syntax Usage Use the SET DEBUG FILE TO statement to name the file that is to hold the run time trace output of a stored procedure BEJ SET DEBUG FILE TO filename T Fi variable name WITH APPEND character expression character expression is any expression that evaluates to a usable filename filename is the full path or filename of the file that contains the trace statement output variable name is a character variable that contains the full path and filename of the file that contains the trace statement output This statement indicates that the output of the procedure TRACE statement goes to the file indicated by filename The WITH APPEND option indicates that output is added to the file if it exists If you do not use the WITH APPEND keyword the f
512. se must equal the number of values supplied in the VALUES clause or by the SELECT statement either implicitly or explicitly If you specify columns the columns receive data in the order in which you list them The first value following the VALUES keyword is inserted into the first column listed the second value is inserted into the second column listed and so on Inserting Rows Through a View 1 246 Syntax You can insert data through a single table view if you have the Insert privilege on the view To do this the defining SELECT statement can select from only one table and it cannot contain any of the following components DISTINCT keyword GROUP BY clause Derived value also referred to as a virtual column e Aggregate value INSERT Columns in the underlying table that are unspecified in the view receive either a default value or a null value if no default is specified If one of these columns does not specify a default value and a null value is not allowed the insert fails You can use data integrity constraints to prevent users from inserting values into the underlying table that do not fit the view defining SELECT statement For further information refer to the WITH CHECK OPTION discussion under the CREATE VIEW statement page 1 138 If several users are entering sensitive information into a single table you can use the USER function to limit the their view to only the specific rows that each inserted The foll
513. ser s login name will be used is a quoted string that is a valid login name The user identifier must be listed in the etc passwd file If the statement connects to a remote server the user identifier must exist in the etc passwd file on both the local and remote servers The User Clause specifies information that is used to determine whether the application can access the target computer when the CONNECT statement connects to the database server on a remote host Subsequent to the CON NECT statement all database operations on the remote host use the specified user name E C CONNECT The connection is rejected if e The specified user lacks the privileges to access the database named in the database environment e The specified user does not have the required permissions to connect to the remote host e You supply a USER clause but do not include the USING auth variable phrase In compliance with the X Open specification for the CONNECT statement the ESQL C and ESQL COBOL preprocessors allow a CONNECT statement that has a USER clause without the USING auth variable phrase The connec tion is rejected at run time by Informix database servers however if the auth variable is not present If you do not supply the USER clause the connection is attempted using the default INFORMIX user ID The default INFORMIX user ID is the login name of the user running the application In this case network permissions are obtained
514. set smallint some sql sqlcode sqlerror sum table to union unique update user values view whenever where with work Although you can use almost any word as an SQL identifier syntactic ambiguities can occur An ambiguous statement might not produce the desired results This section outlines some potential pitfalls and workarounds Syntax 1 471 Identifier Using Functions as Column Names 1 472 Syntax The following two examples show a workaround for using a function as a column name in a SELECT statement This applies to the aggregate functions AVG COUNT MAX MIN SUM as well as the function expressions alge braic exponential and logarithmic time hex length dbinfo and trigonometric functions Using avg as a column name causes the following example to fail because the database server interprets avg as an aggregate function rather than as a column name SELECT avg FROM mytab fails The workaround in following example removes ambiguity by including a table name with the column name SELECT mytab avg FROM mytab If you use the keyword TODAY CURRENT or USER as a column name ambiguity can occur as shown in the following example CREATE TABLE mytab user char 10 CURRENT DATETIME HOUR TO SECOND TODAY DATE INSERT INTO mytab VALUES josh 11 30 30 1 22 89 SELECT user current today FROM mytab The database server interprets user current and tod
515. sion as shown in the following example If the COUNT function encounters nulls it ignores them SELECT COUNT DISTINCT item_num FROM items Nulls are ignored unless every value in the specified column is null If every column value is null the COUNT keyword returns a zero for that column Summary of Aggregate Function Behavior The following example summarizes the action of the aggregate functions SELECT a_number FROM testtable WHERE a_number lt 10 You get the values shown in the following example from the query shown in the preceding example a_number a PBWWNHDY DY null Syntax 1 465 Expression The values returned from the preceding example are shown in the following example Function Results COUNT 7 AVG 2 67 AVG DISTINCT 3 MAX 4 MAX DISTINCT 4 MIN 2 MIN DISTINCT 2 SUM 1 SUM DISTINCT 9 COUNT DISTINCT 3 The following example show a query that returns the value 3 SELECT AVG DISTINCT a_number FROM testtable WHERE a_number lt 10 1 466 Syntax Expression Error Checking with Aggregate Functions Aggregate functions always return one row if no rows are selected the function returns a null You can use the COUNT keyword to determine whether any rows were selected and you can use an indicator variable to determine whether any of the selected rows were empty Fetching a row with a cursor associated with an aggregate function always returns
516. sition form 5 29R for delimiter form 5 25R time to update indexes 10 20T use with insert cursor 1 157S VALUES clause 4 7T with a view 11 25T DECLARE 1 145S SELECT 1 253S with dbload 5 23R Inserting rows of constant data 6 11T Installation directory specifying with INFORMIXDIR 4 36R INT data type See INTEGER data type INTEGER data type changing data types 3 23R description of 3 13R 9 7T syntax 1 425S using as default value 1 195 1 89S Integrity See Data integrity Integrity See Referential integrity Integrity See Semantic integrity Intensity attributes setting INFORMIXTERM for 4 38R Interrupt key with dbexport 5 9R with dbimport 5 14R with dbload 5 21R Interrupted modifications 4 22T IS NOT keywords syntax in Condition INTERVAL data type segment 1 405S adding or subtracting from 3 30R adding or subtracting from DATETIME values 3 27R as quoted string 1 4985 description of 3 13R 9 14T display format 9 16T field delimiters 3 15R field qualifier syntax 1 485S in expression 1 4415 in INSERT 1 498S in relational expressions 2 29T multiplying or dividing values 3 31R precision and size 9 14T range of expressions 3 26R range of operations with DATE and DATETIME 3 25R syntax 1 425S 1 491S with EXTEND function 3 26R 3 28R See also Literal INTERVAL INTERVAL Field Qualifier segment 1 485S INTO keyword choice of location 5 22T in FETCH statement 5 22T in SELECT 1 318S mismatch signalled
517. specify the table synonym or view in which to load the new data See the discussion of Synonym Name Table Name and View Name beginning on page 1 504 for details You must specify the column names only if one of the following conditions is true e You are not loading data into all columns e The input file does not match the default order of the columns determined when the table was created LOAD The following example identifies the price and discount columns as the only columns in which to add data LOAD FROM tmp prices DELIMITER INSERT INTO norman worktab price discount References See the UNLOAD and INSERT statements in this manual In the Informix Guide to SQL Reference see the discussion of the dbload utility in Chapter 5 Syntax 1 259 LOCK TABLE LOCK TABLE Purpose Use the LOCK TABLE statement to control access to a table by other processes Syntax EEA OCK TABLE Meee IN SHARE MODE p 1 506 pg EXCLUSIVE J Synonym Name p 1 504 Usage You can lock a table if you own the table or have the Select privilege on the table or on a column in the table either from a direct grant or from a grant to PUBLIC The LOCK TABLE statement fails if the table is already locked in exclusive mode by another process or if an exclusive lock is attempted while another user has locked the table in share mode The SHARE keyword locks a table in shared mode Shared mode allows
518. ssion 1 462S in SELECT 1 312S use in CREATE INDEX 1 64S in SELECT 1 3138 2 19T no effect in subquery 1 4145 with COUNT function 2 54T Distributed deadlock 7 15T Distributed processing 12 8T Distributions dropping with DROP DISTRIBUTIONS clause 1 396S privileges required to create 1 396S using the HIGH keyword 1 396S using the MEDIUM keyword 1 397S Division symbol arithmetic operator 1 431S DML statements summary 1 65 DOCUMENT keyword use in stored procedures 14 6T Documentation notes Intro 8R Intro 115S 6T Dominant table 3 21T Dormant connection 1 1695 DOS operating system 12 4T DOUBLE PRECISION data type See FLOAT data type DROP AUDIT statement 1 171S DROP CONSTRAINT keywords syntax in ALTER TABLE 1 158 use in ALTER TABLE 1 325 DROP DATABASE statement 1 1725 DROP INDEX statement locks table 7 7T releasing an index 13 34T syntax 1 174S DROP keyword syntax in ALTER TABLE 1 15S use in ALTER TABLE 1 268 DROP SYNONYM statement 1 177S DROP TABLE statement 1 179S DROP TRIGGER statement syntax 1 181S use of 1 181S DROP VIEW statement 1 183S Duplicate index keys 10 22T Duplicate values finding 3 16T in a query 1 313S Dynamic management statements 1 65 Dynamic SQL cursor use with 5 32T description of 5 5T 5 28T freeing prepared statements 5 33T E Editor specifying with DBEDIT 4 18R Effective checking 1 349S Ellipses wildcard in Condition segment 1 411S Embedded SQL define
519. ssion in the GROUP BY clause You cannot use variable names for example host variables in an ESQL application or stored procedure variables in a stored procedure in the select list by themselves You can include a variable name in the select list however if it is connected to a constant by an arithmetic or concatenation operator Syntax 1 313 SELECT 1 314 Syntax Selecting Columns Column expressions are the most common expressions used in a SELECT statement See Column Expressions on page 1 433 for a complete description of the syntax and use of column expressions The following examples show column expressions within a select list SELECT orders order_num items price FROM orders items SELECT customer customer_num ccnum company FROM customer SELECT catalog_num stock_num cat_advert 1 15 FROM catalog SELECT lead_time 2 UNITS DAY FROM manufact Selecting Constants If you include a constant expression in the select list the same value is returned for each row returned by the query See Constant Expressions on page 1 436 for a complete description of the syntax and use of constant expressions The following examples shows constant expressions within a select list SELECT The first name is fname FROM customer SELECT TODAY FROM cust_calls SELECT SITENAME FROM systables WHERE tabid 1 SELECT lead_time 2 UNITS DAY FROM manufact SELECT customer_num LENGT
520. stablishes a connection to a server which is known as an implicit connection If the database statement specifies only a database name the database server name is obtained from the DBPATH environment variable This is described in Locating the Database on page 1 50 An application that makes an implicit connection can establish other connections explicitly using the CONNECT statement but cannot make another implicit connection An application can terminate an implicit connection using the DISCONNECT statement After any implicit connection is made that connection is considered to be the default connection regardless of whether the server is the default specified by the INFORMIXSERVER environment variable This default is to allow the application to refer to the implicit connection if additional explicit connec tions are made because the implicit connection does not have an identifier For example if you establish an implicit connection followed by an explicit connection you can make the implicit connection current by issuing the statement SET CONNECTION DEFAULT This means however that once you CONNECT establish an implicit connection you cannot use the CONNECT DEFAULT command because the implicit connection is considered to be the default connection An application cannot establish an implicit connection if an explicit connection is already established or if an implicit connection has been termi nated The database sta
521. statement is written as part of the declaration of the cursor see the DECLARE statement on page 1 145 In this case the FETCH statement cannot contain an INTO clause The following example uses the INTO clause of SELECT to specify program variables in INFORMIX ESQL C exec sql declare ord_date cursor for select order_num order_date po_num into o_num o_date 0_po exec sql open ord_date exec sql fetch next ord_date You should use an indicator variable if the possibility exists that data returned from the SELECT is null See your SQL API manual for more information about indicator variables Using the INTO Clause of EXECUTE PROCEDURE The EXECUTE PROCEDURE statement that is associated with the cursor can contain an INTO clause that specifies which program variables are to receive the values You can use this method only when the EXECUTE PROCEDURE statement is written as part of the cursor declaration see the DECLARE 1 198 Syntax FETCH statement on page 1 145 In this case the FETCH statement cannot contain an INTO clause The following example uses the INTO clause of EXECUTE PROCEDURE to specify program variables in INFORMIX ESQL C exec sql declare ord_date cursor for execute procedure xx 20 into o_num o_date o_po exec sql open ord_date exec sql fetch next ord_date You should use an indicator variable if the possibility exists that data returned from the EXECUTE PROCEDURE statement is null See your SQ
522. stly read only indexes This option takes affect only when you build an index on a table which contains more than 5000 rows and which use more than 100 table pages The index will be built with the specified FILLFACTOR if it is rebuilt as a result of an archive and rollforward of logs The FILLFACTOR can also be set as a parameter in the ONCONFIG file The FILLFACTOR option on the CREATE INDEX statement overrides the setting in the ONCONFIG file For more information about the ONCONFIG file and the parameters you can use with ONCONFIG see the INFORMIX OnLine Dynamic Server Administra tor s Guide The ASC and DESC Keywords 1 66 Syntax Use the ASC option to specify an index that is maintained in ascending order The ASC option is the default ordering scheme Use the DESC option to spec ify an index that is maintained in descending order When a column or list of columns is defined as unique in a CREATE TABLE or ALTER TABLE statement the database server implements that UNIQUE CONSTRAINT by creating a unique ascending index Thus you cannot use the CREATE INDEX statement to add an ascending index to a column or column list already defined as unique You can create a descending index on such columns and you can include such columns in composite ascending indexes in different combinations For example the following sequence of statements is allowed CREATE TABLE customer customer_num fname iname company addressl
523. straints placed on the multiple columns are also dropped This triggers the dropping of all referential constraints that ref erence the multiple columns Because any constraints associated with a column are dropped when the col umn is dropped the structure of other tables may also be altered when you use this clause For example if the dropped column is a unique or primary key that is referenced in other tables those referential constraints also are dropped This means that the structure of those other tables have also been altered When you drop a column that occurs in the triggering column list of an UPDATE trigger the column is dropped from the triggering column list If the column is the only member of the triggering column list the trigger is dropped from the table See CREATE TRIGGER on page 1 110 for more information on triggering columns in an UPDATE trigger ALTER TABLE MODIFY Clause MODIFY Clause t gt MODIFY Moai Eom a J em Clause Modify Column Clause gt lumn Data Type co u E name p 1 424 DEFAULT a a of ause p 1 18 Sita ew Column Constraint Definition p 1 20 column name is the name of the existing column that you wish to modify Use the MODIFY clause to change the data type of a column and the length of a character column to add or change the default value for a column and to allow or disallow nulls in a column When
524. t 1 194 Syntax Usage X O FETCH indicator is a program variable that receives a return code if null data variable is placed in the corresponding data variable row position is an integer or variable that contains an integer value giving the position of the desired row in the active set of rows sqlda pointer is a pointer to an sqlda structure that receives the values from the fetched row The FETCH statement is one of four statements used for queries that return more than one row from the database The four statements DECLARE OPEN FETCH and CLOSE are used in the following sequence 1 Declare a cursor to control the active set of rows 2 Open the cursor to begin execution of the query 3 Fetch from the cursor to retrieve the contents of each row 4 Close the cursor to break the association between the cursor and the active set A cursor is created as either a sequential cursor or a scroll cursor The way the database server creates and stores members of the active set and then fetches rows from the active set differs depending on whether the cursor is a sequen tial cursor or a scroll cursor See the DECLARE statement on page 1 145 for details on the types of cursors In X Open mode if a cursor direction value such as NEXT or RELATIVE is specified a warning message is issued indicating that the statement does not conform to X Open standards FETCH with a Sequential Cursor A sequential cursor can f
525. t See the PREPARE statement on page 1 273 The DESCRIBE statement allows you to determine at run time the type of statement that has been prepared and the number and types of data that a prepared query returns when executed With this information you can write code to allocate memory to hold retrieved values and display or process them after they are fetched DESCRIBE Describing the Statement Type The DESCRIBE statement takes a statement identifier from a PREPARE statement as input When the DESCRIBE statement executes the database server sets the value of the SQLCODE field of the sqlca see the manual for your embedded language product to indicate the statement type that is the keyword with which the statement begins If the prepared statement text con tains more than one SQL statement the DESCRIBE statement returns the type of the first statement in the text SQLCODE is set to zero to indicate a SELECT statement without an INTO TEMP clause This is the most common situation For any other SQL statement SQLCODE is set to a positive integer Look in the embedded SQL manual for your embedded product for more information about possible SQLCODE val ues after a DESCRIBE statement You can test the number against the constant names that are defined In INFORMIX ESQLIC the constant names are defined in the sqlstype h header file A printed list of the possible values and their constant names appears in the manual for each embedd
526. t WHERE id SELECT cl c2 INTO c d FROM t WHERE id END PROCEDURE an ll pa SPL Statements 2 29 LET If the SELECT statement returns more than one row the SELECT statement must be enclosed in a FOREACH loop Calling a Procedure in a LET Statement 2 30 SPL Statements You can call a procedure in a LET statement and assign the returned values to variables If the LET statement includes a procedure call itinvokes the named procedure You must specify all the necessary arguments to the procedure in the LET statement unless the procedure has default values for its arguments If you use the called variable syntax for one of the parameters in the called procedure you must use it for all the parameters The variable name receives the returned value from a procedure call A procedure can return more than one value into a list of variable names A procedure that returns more than one row must be enclosed in a FOREACH loop The following example shows two valid LET statements that contain procedure calls The third LET statement is not legal because it tries to have the output of two procedures added and then assigned to two variables a and b This LET statement can be split easily into two legal LET statements LET a b c procl name grok age 17 LET a b c 7 proc orange green LET a b procl proc2 ILLEGAL CODE ON EXCEPTION ON EXCEPTION Purpose Use the
527. t buffer counting inserted rows 1 205S 1 290S filling with constant values 1 2865 inserting rows with a cursor 1 2485 storing rows with PUT 1 285S triggering flushing 1 289S Insert cursor 1 148S closing 1 395 definition of 1 148S 6 8T in INSERT 1 248S in PUT 1 286S opening 1 266S reopening 1 2675 result of CLOSE in SQLCA 1 398 use of 1 149S 6 11T with hold 1 157S writing buffered rows with FLUSH 1 204S INSERT INTO keywords in INSERT 1 245S in LOAD 1 258S INSERT keyword syntax in GRANT 1 235S in REVOKE 1 301S use in GRANT 1 236S in REVOKE 1 302S Insert privilege 11 8T 11 28T INSERT REFERENCING clause and FOR EACH ROW section 1 121S correlation name 1 118S syntax 1 118S INSERT STATEMENT using functions in the VALUES clause 1 252S INSERT statement and end of data 6 14T character position form 5 28R constant data with 6 11T count of rows inserted 6 11T delimiter form 5 24R duplicate values in 4 7T effect of transactions 1 249S embedded 6 8T to 6 14T filling insert buffer with PUT 1 285S in dynamic SQL 1 2535 in trigger event 1 111S in triggered action 1 1225 inserting multiple rows 4 9T nulls with the VALUES clause 1 252S rows 4 6T rows through a view 1 2465 rows with a cursor 1 248S single rows 4 7T values into SERIAL columns 3 19R null values in 4 7T number of rows 5 12T privilege for 11 6T 11 8T SELECT statement in 4 9T SERIAL columns 1 251S specifying values to insert 1 250S syntax 1 245S for character po
528. t is any real number represents an expression that evaluates to an integer It is any real number represents an expression that evaluates to a numeric value It is any real number represents an expression of which you are determining the root It is any real number Nradicand indicates the digit to which you want to round the expression This digit must be an integer between 32 and 32 inclusive indicates the position to which you want to truncate the expression This digit must be an integer between 32 and 32 inclusive The ABS function gives the absolute value for a given expression The function requires a single numeric argument The value returned is the same as the argument type The following example shows all orders of more than 20 paid in cash or store credit Remember that the stores6 database does not contain any negative balances however you may have negative balances in your application SELECT order_num customer_num ship_charge FROM orders WHERE ABS ship_charge gt 20 Syntax 1 445 Expression 1 446 Syntax MOD Function The MOD function returns the modulus or remainder value for two numeric expressions You provide integer expressions for the dividend and divisor The divisor cannot be 0 The value returned is INT The following example uses a 30 day billing cycle to determine how far into the billing cycle today is SELECT MOD today MDY 1 1 year today 30 FRO
529. t of col umns the constraint shares the index However if the existing index allows duplicates the database server returns an error You must then drop the existing index before adding the constraint When you place a unique or primary key constraint on a column or set of columns and a referential constraint already exists on that column or set of columns the duplicate index is upgraded to unique if possible and the index is shared When you place a referential constraint on a column or set of columns and a referential constraint already exists on that column or set of columns the duplicate index is upgraded to unique if possible and the index is shared An existing unique constraint cannot have the same name as the constraint you are adding A composite list can include no more than 16 column names The total length of all the columns cannot exceed 255 bytes When you own the table or have the Alter privilege on the table you can create a unique primary key or check constraint on the table and specify yourself as the owner of the constraint To add a referential constraint you must have References privilege on either the referenced columns or the refer enced table When you have the DBA privilege you can create constraints for other users Syntax 1 31 ALTER TABLE DROP CONSTRAINT Clause DROP CONSTRAINT Clause DROP CONSTRAINT Nate gt p 1 419 2i a 2 p 1 419 To
530. t variables see Chapter 4 of the Informix Guide to SQL Reference For information about sqlhosts see the INFORMIX OnLine Dynamic Server Administrator s Guide or the INFORMIX SE Administrator s Guide 2 Create anew directory for the SQL command files Create the directory by entering mkdir dirname 3 Make the new directory the current directory by entering cd dirname 4 Create the demonstration database and copy over the sample command files by entering the following command To create the database without logging enter dbaccessdemo6 dbname To create the demonstration database with logging enter dbaccessdemo6 log dbname If you are using INFORMIX OnLine Dynamic Server by default the data for the database is put into the root dbspace If you wish you can specify a dbspace for the demonstration database To create a demonstration database in a particular dbspace enter dbaccessdemo6 dbspacename If you are using INFORMIX SE a subdirectory called dbname dbs is created in your current directory and the database files associated with stores6 are placed there You will see both data dat and index idx files Introduction 13 New Features in Informix Version 6 0 Products That Use SQL in the dbname dbs directory If you specify a dbspace name it will be ignored To use the database and the command files that have been copied to your directory you must have UNIX read and execute permissions for each directory
531. tabase Name Database Name Purpose Syntax Use the Database Name syntax wherever you see a reference to a database name in a syntax diagram The Database Name segment is used in the following statements CREATE DATABASE DATABASE DROP DATABASE ROLLFORWARD DATABASE START DATABASE dbname we one dbservername A dbservername dbname N dbservername pathname dbname A variable name A pathname dbname abservername dbname is the name of the database itself The dbname must conform to the same rule as any identifier as described in Identifier on page 1 469 dbservername is the name of the database server that is home to the database The symbol is a literal character that you must use to introduce the database server name pathname is the path of the database directory up to the parent directory of the dbs directory variable name is a program or host variable that contains the name of a database Syntax 1 421 Database Name Usage The simple database name is an SQL identifier as described on page 1 469 If you are creating a database the name that you assign to the database can be 18 characters inclusive Database names are not case sensitive Database names in INFORMIX SE databases can be 10 characters inclusive The maximum length of the database name and directory path including dbservername is 128 characters The following example shows a data
532. table SELECT item_num order_num quantity stock_num manu_code total_price FROM items Detailed information on SELECT statement syntax is provided on page 1 310 Using INSERT as a Dynamic Management Statement You can use the INSERT statement to handle situations where you need to write code that can insert data whose structure is unknown at the time you compile For more information refer to the dynamic management section of your SQL API manual Syntax 1 253 INSERT Inserting Data Using a Stored Procedure You can insert the rows of data that result from a procedure call into a table The values returned by the procedure must match those expected by the column list in number and data type The number and data types of the columns must match those expected by the column list References See the SELECT statement in this manual Also see the DECLARE DESCRIBE EXECUTE FLUSH OPEN PREPARE and PUT statements in this manual for specific information about dynamic management statements In the Informix Guide to SQL Tutorial see the discussion of inserting data in Chapter 4 and Chapter 6 1 254 Syntax LOAD LOAD Purpose Syntax E oan FROM Use the LOAD statement to insert data from an ASCII operating system file into an existing table synonym or view Hs filename DELIMITER rl delimiter 9 INSERT INTO table Usage Name p 1 506 A Synonym Name p 1 504
533. table name SELECT The following multiple table join yields the company name of the customer who ordered an item as well as the stock number and manufacturer code of the item SELECT DISTINCT company stock_num manu_code FROM customer c orders o items i WHERE c customer_num o customer_num AND o order_num i order_num Self Joins You can join a table to itself To do so you must list the table name twice in the FROM clause and assign it two different table aliases Use the aliases to refer to each of the two tables in the WHERE clause The following example is a self join on the stock table It finds pairs of stock items whose unit prices differ by a factor greater than 2 5 The letters x and y are each aliases for the stock table SELECT x stock_num x manu_code y stock_num y manu_code FROM stock x stock y WHERE x unit_price gt 2 5 y unit_price Outer Joins The following outer join lists the company name of the customer and all associated order numbers if the customer has placed an order If not the company name is still listed and a null value is returned for the order number SELECT company order_num FROM customer c OUTER orders o WHERE c customer_num o customer_num See Chapter 3 of the Informix Guide to SQL Tutorial for more information about outer joins Syntax 1 333 SELECT GROUP BY Clause Use the GROUP BY clause to produce a single row of results
534. tell us what you like or dislike about this manual To help us with future ver sions of the manual please tell us about any corrections or clarifications that you would find useful Return this card to Informix Software Inc Technical Publications Department 4100 Bohannon Drive Menlo Park CA 94025 If you prefer to share your comments on line address your e mail to doc informix com Related Reading If you want additional technical information on database management consult the following texts by C J Date e An Introduction to Database Systems Volume I Addison Wesley Publishing 1990 e An Introduction to Database Systems Volume II Addison Wesley Publishing 1983 This guide assumes that you are familiar with your computer operating system If you have limited UNIX system experience you might want to look at your operating system manual or a good introductory text before you read this manual Some suggested texts about UNIX systems follow e A Practical Guide to the UNIX System Second Edition by M Sobell Benjamin Cummings Publishing 1989 e A Practical Guide to UNIX System V by M Sobell Benjamin Cummings Publishing 1985 e Introducing the UNIX System by H McGilton and R Morgan McGraw Hill Book Company 1983 UNIX for People by P Birns P Brown and J Muster Prentice Hall 1985 If you are interested in learning more about the SQL language consider the following text e Using SQL by
535. tem catalog table See the GRANT and REVOKE statements for more information about database and table access privileges Syntax 1 243 INFO Figure 1 10 1 244 Syntax Use the STATUS FOR keyword to display information about the owner row length number of rows and columns creation date and status of audit trails for a specified table The following example shows an INFO statement Figure 1 10 displays status information for a table on an INFORMIX SE database server INFO STATUS FOR cust_calls INFO statement requesting status information Table Name cust calls Owner velma Row Size 517 Number of Rows 7 Number of Columns T Date Created 01 28 1993 Audit Trail File Display of status information The audit trail file line does not appear for tables on the INFORMIX OnLine Dynamic Server INSERT INSERT Purpose Use the INSERT statement to insert one or more new rows into a table or view Syntax VALUES Clause INSERT INTO a p 1 250 J column 2 SELECT name N Statement Subset p 1 253 j P re pRocepuRE cedure _ p 1 495 i Argument Argument Expression a p 1 430 p 2s parameter _ re name SELECT Statement Singleton p 1 310 column name is the column that receives the new data parameter name is the name of the parameter as defined by its CREATE PROCEDURE statement Usage You c
536. tement a null value is inserted into any column for which you do not provide a value as well as for all columns that do not have default values associated with them which not listed explicitly You also can use the NULL keyword to indicate that a column should be assigned a null value The following example inserts values into three columns of the orders table INSERT INTO orders orders_num order_date customer_num VALUES 0 NULL 123 In this example a null value is explicitly entered in the order_date column and all other columns of the orders table not explicitly listed in the INSERT INTO clause are also filled with null values INSERT Subset of SELECT Statement You can insert the rows of data that result from a SELECT statement into a table if the insert data is selected from another table or tables If this statement has a WHERE clause that does not return rows sqlca returns SOQLNOTFOUND 100 for ANSI compliant databases In databases that are not ANSI compli ant sqlca returns 0 When you insert as a part of a multistatement prepare and no rows are inserted sqlca returns SOLNOTFOUND 100 for both ANSI and databases that are not ANSI compliant The following SELECT clauses are not supported INTO TEMP ORDER BY e UNION In addition the FROM clause of the SELECT statement cannot contain the same table name as the table into which you are inserting rows as shown in the following example INSERT INTO new
537. tements can always be used to open a database or create a new database on the current server The WITH CONCURRENT TRANSACTION Option The WITH CONCURRENT TRANSACTION clause lets you switch to a different connection while a transaction is active in the current connection If the cur rent connection was not established using the WITH CONCURRENT TRANS ACTION clause you cannot switch to a different connection if a transaction is active the CONNECT or SET CONNECTION statement fails returning an error and the transaction in the current connection continues to be active In this case the application must commit or roll back the active transaction in the current connection before switching to a different connection The WITH CONCURRENT TRANSACTION clause supports the concept of multiple concurrent transactions in which each connection can have its own transaction and the COMMIT WORK and ROLLBACK WORK statements affect only the current connection The WITH CONCURRENT TRANSACTION clause does not support global transactions in which a single transaction spans data bases over multiple connections The COMMIT WORK and ROLLBACK WORK statements do not act on databases across multiple connections Figure 1 1 illustrates how to use the WITH CONCURRRENT TRANSACTION clause main EXEC SQL CONNECT TO a srvl AS A EXEC SQL CONNECT TO b srv2 AS B WITH CONCURRENT TRANSACTION EXEC SQL CONNECT TO c srv3 AS C WITH CONCURRENT TRANSACTION
538. tements or cursors The term statement identifier means statement id or statement id variable Statement Identifier A PREPARE statement sends the statement text to the database server where it is analyzed If it contains no syntax errors the text converts to an internal form This translated statement is saved for later execution in a data structure that the PREPARE statement allocates The structure has the name statement identifier Subsequent SQL statements refer to the statement using the statement identifier A subsequent FREE statement releases the resources allocated to the statement After you release the database server resources you cannot use the statement identifier with a DECLARE cursor or with the EXECUTE statement until you prepare the statement again A program can consist of one or more source code files By default the scope of a statement identifier is global to the program This means that a statement identifier prepared in one file can be referenced from another file Ina multiple file program if you want to limit the scope of a statement iden tifier to the file in which it is prepared preprocess all the files with the local command line option See your ESOL product manual for more information restrictions and performance issues when preprocessing with the local option Releasing a Statement Identifier 1 274 Syntax A statement identifier can represent only one SQL statement or sequence of statemen
539. tements to specify the name of a view CREATE SYNONYM CREATE VIEW DELETE DROP VIEW GRANT INSERT REVOKE SELECT UPDATE Syntax Identifier p 1 469 gt owner Ke owner database I Pa y dbservername database is the name of the database in which the view resides dbservername is the name of the INFORMIX OnLine Dynamic Server database server that is home to database The sign is a literal character that you must use to introduce the database server name owner is the user name of the owner of the view If you are using an ANSI compliant database you must use the owner conven tion for views that you do not own If you use quotes owner appears exactly as typed 1 510 Syntax View Name Usage The use of the prefix owner is optional however if you use it the database server does check owner for accuracy If you are creating a view the name of the view must be unique among all the tables synonyms temporary tables and views that already exist in the database IW Ifyou are creating a view the owner view name must be unique among all the tables synonyms and views that already exist in the database The owner name is case sensitive In an ANSI compliant database if you do not use quotes around the owner name the name of the table owner is stored as uppercase letters For more information see the discussion of case sensitivity in ANSI compliant databases on page 1 508
540. tes immediately Syntax 1 383 UPDATE Updating Rows Through a View You can update data through a single table view if you have the Update privilege on the view see the GRANT statement on page 1 231 To do this the defining SELECT statement can select from only one table and it cannot contain any of the following elements DISTINCT keyword GROUP BY clause Derived value also called a virtual column e Aggregate value You can use data integrity constraints to prevent users from updating values into the underlying table that do not fit the view defining SELECT statement For further information refer to the WITH CHECK OPTION discussion in the CREATE VIEW statement on page 1 136 Because duplicate rows can occur in a view even though the underlying table has unique rows be careful when you update a table through a view For example if a view is defined on the items table and contains only the order_num and total_price columns and if two items from the same order have the same total price the view contains duplicate rows In this case if you update one of the two duplicate total price values you have no way to know which item price is updated Note You cannot update rows to a remote table through views with check options Updating Rows in a Database Without Transactions 1 384 Syntax If you are updating rows in a database without transactions you must take explicit action to restore updated rows For example
541. th the display label to clarify the use of the word If you want to use the word UNITS YEAR MONTH DAY HOUR MINUTE SECOND or FRACTION as your SELECT display label you must use the AS keyword with the display label The following example shows how to use the AS keyword to use minute as a display label SELECT call_dtime AS minute FROM cust_calls Syntax 1 317 SELECT INTO Clause 1 318 Syntax Use the INTO clause within a stored procedure or SQL API to specify the program variables or host variables to receive the data retrieved by the SELECT statement The syntax of the INTO clause is as shown in the following diagram INTO Clause p INTO C data variable 7 2 p A indicator variable INDICATOR indicator variable A Ne data structure A data variable is a program variable or host object that agrees in type and order with the corresponding columns or expressions in the select list data structure is a structure which has been declared as a host variable The individual elements of the structure must be matched appropriately to the type of values being selected indicator variable is a program variable that receives a return code if null data is placed in the corresponding data variable If the SELECT statement stands alone that is it is not part of a DECLARE statement and does not use the INTO clause it must be a singleton SELECT statement A singleton SEL
542. the ON EXCEPTION Statement Block To prevent an infinite loop if an error occurs during execution of the statement block of an error trap the search for another trap does not include the current trap SPL Statements 2 35 RAISE EXCEPTION RAISE EXCEPTION Purpose Syntax Usage 2 36 SPL Statements Use the RAISE EXCEPTION statement to simulate the generation of an error SQL na RAISE EXCEPTION 5 75 A ISAM pa error TN 7g No error _ gt text error text is a quoted string or variable that contains a string to be returned by the SQL error ISAM error is an SPL expression that evaluates to an integer value that is a valid ISAM error number SQL error is an SPL expression that evaluates to an integer value that is a valid SQL error number The RAISE EXCEPTION statement is used to simulate an error The generated error can be trapped by an ON EXCEPTION statement If the ISAM error expression is omitted the ISAM error code is set to zero when the exception is raised If you want to use the error text field but not specify the ISAM error number portion you can specify the ISAM error to be zero For example the following statement raises the error number 99999 and returns the stated text RAISE EXCEPTION 99999 0 You broke the rules The exceptions raised can be either system or user generated In the following example if the value of a is negative exception 99999 is raised An ON
543. the SUBCLASS_ORIGIN keyword to define the source of the subclass portion of the RETURNED_SOLSTATE value If the ISO international standard defines the subclass the value of SUBCLASS_ORIGIN is equal to ISO 9075 Using the MESSAGE_TEXT Keyword Use the MESSAGE_TEXT keyword to determine the message text of the exception for example an error message Using the MESSAGE_LENGTH Keyword Use the MESSAGE_LENGTH keyword to determine the length of the current MESSAGE_ TEXT string Using the SERVER_NAME Keyword Use the SERVER_NAME keyword to determine the name of the server or servers associated with the actions of a CONNECT or DATABASE statement When the SERVER_NAME Field is Updated The GET DIAGNOSTICS statement updates the SERVER_NAME field when the following situations occur A CONNECT statement successfully executes A SET CONNECTION statement successfully executes A DISCONNECT statement successfully executes at the current connection e A DISCONNECT ALL statement fails Syntax 1 225 GET DIAGNOSTICS When the SERVER_NAME Field is not Updated The SERVER_NAME field is not updated when A CONNECT statement fails e A DISCONNECT statement fails Note This does not include the DISCONNECT ALL statement A SET CONNECTION statement fails Note The SERVER_NAME field retains the value set in the previous SQL statement If any of the three preceding conditions occur on the first SQL statement that executes the SERVE
544. the decimal point as shown in Figure 1 17 expression 24536 8746 ROUND 24 536 8746 2 24 500 00 ROUND 24 536 8746 0 24 537 00 2 0 2 ROUND 24 536 8746 2 24 536 87 ROUND function SELECT order_num ROUND total_price FROM items WHERE ROUND total_price 124 00 If you use a MONEY data type as the argument for the ROUND function and you round to zero places the value displays with 00 The SELECT statement in the following example rounds an INTEGER value and a MONEY value It displays 125 and a rounded price in the form xxx 00 for each row in items SELECT ROUND 125 46 ROUND total_price FROM items SQRT Function The SQRT function returns the square root of a numeric expression The following example returns the square root of 9 for each row of the angles table SELECT SQRT 9 FROM angles TRUNC Function The TRUNC function returns the truncated value of a numeric expression The expression must be numeric or of a form that can be converted to a numeric expression If you omit the digit indication the value is truncated to zero digits or to the ones place The digit limitation of 32 and refers to the entire decimal value Syntax 1 447 Expression Figure 1 18 Positive digit values indicate truncating to the right of the decimal point negative digit values indicate truncating to the left of the decimal point as shown in Figure 1 18 expression 24536 8746
545. the row that was changed by the triggering statement to its previous value When you use a stored procedure as a triggered action if you terminate the procedure in an exception handling section any actions that modify data inside that section are rolled back along with the triggering statement In the following partial example when the exception handler traps an error it inserts a row into the table logtab ON EXCEPTION IN 201 INSERT INTO logtab values errno errstr RAISE EXCEPTION 201 END EXCEPTION When the RAISE EXCEPTION statement returns the error however the database server rolls back this insert because it is part of the triggered actions If the procedure is executed outside a triggered action the insert is not rolled back CREATE TRIGGER The stored procedure that implements a triggered action cannot contain any BEGIN WORK COMMIT WORK or ROLLBACK WORK statements If the data base has logging you must either begin an explicit transaction before the trig gering statement or the statement itself must be an implicit transaction In any case another transaction related statement cannot appear inside the stored procedure You can use triggers to enforce referential actions that the database server does not currently support Again however for an INFORMIX SE database or for an INFORMIX OnLine Dynamic Server database without logging you are responsible for maintaining data integrity when the trigg
546. thout Transactions 1 248 Syntax If you are inserting rows into a database without transactions you must take explicit action to restore inserted rows after a failure For example if the INSERT statement fails after inserting some rows the successfully inserted rows remain in the table You cannot recover automatically from a failed insert INSERT Inserting Rows into a Database with Transactions If you are inserting rows into a database with transactions and you are using explicit transactions you can undo the insertion using the ROLLBACK WORK statement If you do not execute BEGIN WORK before the insert and the insert fails the database server automatically rolls back any database modifications made since the beginning of the insert If you are inserting rows into an ANSI compliant database transactions are implicit and all database modifications take place within a transaction In this case if an INSERT statement fails you can use the ROLLBACK WORK statement to undo the insertions If you are using INFORMIX OnLine Dynamic Server within an explicit transaction and the update fails the database server automatically undoes the effects of the update Rows that you insert within a transaction remain locked until the end of the transaction The end of a transaction is either a COMMIT WORK statement where all modifications are made to the database or ROLLBACK WORK state ment where none of the modifications are made to the data
547. tial constraints placed on the column by other tables are dropped For example a column is part of a multiple column primary key constraint This primary key is refer enced by foreign keys in two other tables When this column is modified the multiple column primary key constraint is not dropped but the referential constraints placed on it by the two other tables are dropped When you modify a column that appears in the triggering column list of an UPDATE trigger the trigger is unchanged Altering the Structure of Tables 1 28 Syntax When you use the MODIFY clause you can also alter the structure of other tables If the modified column is referenced by other tables those referential constraints are dropped You must add those constraints to the referencing tables again using the ALTER TABLE statement When you change the data type of an existing column all data is converted to the new data type including numbers to characters and characters to num bers if the characters represent numbers The following statement changes the data type of the quantity column ALTER TABLE items MODIFY quantity CHAR 6 When a unique or primary key constraint exists however conversion takes place only if it does not violate the constraint If a data conversion results in duplicate values by changing FLOAT to SMALLFLOAT for example or by truncating CHAR values then the ALTER TABLE statement fails ALTER TABLE Modifying Tables
548. ting 1 2325 passing grant ability 1 237S revoking 1 303S See also Privilege DATE data type converting to DATETIME 3 25R description of 3 7R 9 12T functions in 1 454S 2 56T in ORDER BY sequence 2 14T range of operations 3 25R representing DATE values 3 29R syntax 1 425S using with DATETIME and INTERVAL values 3 28R DATE function as time function 2 56T syntax in expression 1 4545 use in expression 1 455S 2 61T DATE value setting DBDATE environment variable 4 16R specifying European format with DBDATE 4 17R DATETIME data type 4GL example 13 6T adding or subtracting INTERVAL values 3 27R as quoted string 1 498S character string values 3 10R converting to DATE 3 25R description of 9 12T displaying format 2 61T 9 16T field qualifiers 3 8R 1 428S functions on 2 56T in expression 1 4415 INSERT 1 498S ORDER BY sequence 2 14T relational expressions 2 29T multiplying values 3 26R precision and size 3 8R 9 13T range of expressions 3 26R range of operations with DATE and INTERVAL 3 25R representing DATETIME values 3 29R syntax 1 4255 1 4885 using the DBTIME environment variable 4 27R with EXTEND function 3 26R 3 28R See also Literal DATETIME DATETIME Field Qualifier segment 1 4285 DATETIME formats using the DBTIME environment variable 4 27R Date representing with NLS 1 15R DAY function as time function 2 57T syntax in expression 1 454S use as time function 2 56T in expression 1 455S
549. ting the work of keeping the list results in a performance benefit If you do not use the OF keyword the database server keeps the list of updated rows even though it might be unnecessary The following example contains INFORMIX ESQL C code that uses an update cursor with a DELETE statement to delete the current row Whenever the row is deleted the cursor remains between rows After you delete data you must use a FETCH statement to advance the cursor to the next row before you can refer to the cursor in a DELETE or UPDATE statement exec sql declare q_curs cursor for select from customer where lname matches last_name for update exec sql open q_curs for 77 exec sql fetch q_curs into cust_rec if sqlca sqlcode 0 break Display customer values and prompt for answer if answer 0 y exec sql delete from customer where current of q_curs if sqlca sqlcode 0 break exec sql close q_curs Associating a Cursor with a Prepared Statement 1 154 Syntax The PREPARE statement lets you assemble the text of an SQL statement at run time and pass the statement text to the database server for execution If you anticipate that a dynamically prepared SELECT statement or EXECUTE PRO CEDURE statement that returns values could produce more than one row of data the prepared statement must be associated with a cursor See the PRE PARE statement on page 1 273 for more information about preparing SQL stat
550. tion You can only use the single quote with the quoted string to match a literal quote you cannot use the ESCAPE keyword You can use the quote character as the ESCAPE character in matching any other pattern if you writeitas Syntax 1 409 Condition 1 410 Syntax NOT Option The NOT option makes the search condition successful when the column on the left has a value that is not null and does not match the pattern specified by the quoted string For example the following conditions exclude all rows that begin with the characters Baxter in the Iname column WHERE lname NOT LIKE BaxterS WHERE lname NOT MATCHES Baxter LIKE Option If you use the keyword LIKE you can use the following wildcard characters in the quoted string matches zero or more characters matches any single character removes the special significance of the next character used to match or _ by writing or _ Using the backslash as an escape character is an Informix extension to ANSI compliant SQL If you use an escape character to escape anything other than or _ an error is returned The following condition tests for the string tennis alone or in a longer string such as tennis ball or table tennis paddle WHERE description LIKE tennis The following condition tests for all descriptions that contain an underscore The backslash is necessary because the underscore is a wil
551. tion is a DBA privileged procedure When you are granted the Execute privilege on the procedure the server automatically grants you DBA privileges for the procedure execution These DBA privileges are available only to you when you are executing the procedure 2 The triggered action is an owner privileged procedure If the procedure owner has the WITH GRANT OPTION right for the neces sary privileges on the underlying objects you inherit these privilege when you are granted the Execute privilege In this case all the nonqual ified objects that the procedure references are qualified by the name of the procedure owner If the procedure owner does not have the WITH GRANT OPTION privilege you have your original privileges on the underlying objects when the procedure executes For more information on privileges on stored procedures see Chapter 14 in the Informix Guide to SQL Tutorial Creating a Triggered Action Anyone Can Use To create a trigger that is executable by anyone who has the privileges to exe cute the triggering statement you can ask the DBA to create a DBA privileged procedure and grant you the Execute privilege with the WITH GRANT OPTION privilege You then use the DBA privileged procedure as the trig gered action Anyone can execute the triggered action because the Syntax 1 129 CREATE TRIGGER DBA privileged procedure carries the WITH GRANT OPTION privilege When you activate the procedure the database server
552. tion segment 1 404S Index 31 use in Condition segment 1 417S OR logical operator 2 36T OR relational operator 2 33T ORDER BY keywords and NLS 2 25T ascending order 1 338S 2 14T DESC keyword 2 15T 2 25T descending order 1 338S display label with 2 52T indexes for 13 10T 13 34T multiple columns 2 15T relation to GROUP BY 3 7T restrictions in INSERT 1 253S 4 10T restrictions in view 11 22T restrictions with FOR UPDATE 6 8T select columns by number 1 339S 2 24T sorting rows 2 13T 13 12T syntax in SELECT 1 310S use in SELECT 1 337S with UNION operator 1 344S Order of execution of action statements 1 122S orders table in stores6 database columns in A 3R Outer join forming 1 324S OUTER keyword with FROM keyword in SELECT 1 323S Output from TRACE command 15 14T OUTPUT statement syntax and use 1 271S Owner in ALTER TABLE 1 16S in CREATE SYNONYM 1 808 in dbschema 5 35R in Index Name segment 1 419S 1 484S 1 495S 1 505S in RENAME COLUMN 1 294S in RENAME TABLE 1 296S in Table Name segment 1 4698S 1 507S in View Name segment 1 510S of view in CREATE VIEW 1 5115S Owner privileged procedure 14 13T Ownership 11 7T P Page buffer cost of nonsequential access 13 18T description of 13 16T effect on performance 13 17T restrictions with BLOB data 10 19T PAGE keyword use in ALTER TABLE 1 335 use in CREATE TABLE 1 108S Page lock 7 8T Page definition of 10 4T Parameter BYTE or TEXT in SPL 2 135 in CALL statement 2 4
553. tion very carefully because COMMIT WORK releases all locks even ones placed through a hold cursor Using FOR UPDATE with a List of Columns When you declare an update cursor you can limit the update to specific columns by including the OF keyword and a list of columns You can modify only those named columns in subsequent UPDATE statements The columns need not be in the select list of the SELECT clause This column restriction applies only to UPDATE statements The OF column clause has no effect on subsequent DELETE statements that use a WHERE CURRENT OF clause A DELETE statement removes the contents of all columns The principal advantage to specifying columns is documentation and preventing programming errors The database server refuses to update any other columns An additional advantage is speed when the SELECT statement meets two criteria The SELECT statement can be processed using an index The columns listed are not part of the index used to process the SELECT statement If the columns you intend to update are part of the index used to process the SELECT statement the database server must keep a list of each row that is updated to ensure that no row is updated twice When you use the OF Syntax 1 153 DECLARE keyword to specify the columns that can be updated the database server determines whether to keep the list of updated rows If the database server determines that the list is unnecessary then elimina
554. to assign values to a system descriptor area Syntax xis SET DESCRIPTOR descriptor COUNT T value count E descriptor variable variable item tem VALUE number Descriptor Information item number variable Item Descriptor Information fe TYPE literal integer 7 p X LENGTH be vegi N PRECISION RR SCALE NN NULLABLE N INDICATOR N TYPE N ILENGTH N IDATA q Literal DATETIME Literal INTERVAL NJ p 1 490 NAME oa Quoted String p 1 497 w data variable a Literal Number N Z DATA Je p 1 493 A B A count variable is a variable that holds a literal integer that specifies how many items are being described in the system descriptor Syntax 1 353 SET DESCRIPTOR Usage 1 354 Syntax data variable descriptor descriptor variable integer host variable item number item number variable literal integer value area The value must be less than or equal to the number of occurrences in the system descriptor area which is set when the area is allocated is a host variable that contains the information appropriate for the field being set is a string that identifies a currently allocated system descriptor area is an embedded variable name that contains a string that identifies a currently allocated system descriptor area is the name of a variable that contains an integer value that is appropriate for the indicated
555. to drop a unique constraint created with a CREATE TABLE statement you must use the ALTER TABLE statement to remove indexes created as constraints with a CREATE TABLE or ALTER TABLE statement The index is not actually dropped if it is shared by constraints Instead it is renamed in the sysindexes system catalog table using the following format space lt tabid gt _ lt constraint id gt where tabid and constraint_id are from the systables and sysconstraints system catalog tables respectively The idxname index name column in sysconstraints is then updated to reflect this change For example the renamed index name may be something like this 121_13 quotes used to show the spaces DROP INDEX If this index is a unique index with only referential constraints sharing it the index is downgraded to a duplicate index after it is renamed You cannot use a ROLLBACK WORK statement to undo a DROP INDEX statement If you roll back a transaction that contains a DROP INDEX statement the index is not re created and you do not receive an error message References See the ALTER TABLE CREATE INDEX and CREATE TABLE statements in this manual In the Informix Guide to SQL Tutorial see the discussion of indexes in Chapter 10 Syntax 1 175 DROP PROCEDURE DROP PROCEDURE Purpose Use the DROP PROCEDURE statement to remove a procedure from the database Syntax DROP PROCEDURE
556. to whom the CREATE SCHEMA statement block and the objects created by the block belongs Syntax 1 77 CREATE SCHEMA Usage You cannot issue the CREATE SCHEMA statement until you create the affected database Users with Resource privilege can create a schema for themselves In this case user name is the name of the person with the Resource privilege running the CREATE SCHEMA statement Anyone with the DBA privilege also can cre ate a schema for someone else In this case user name can identify a user other than the person running the CREATE SCHEMA statement You can put CREATE and GRANT statements in any logical order within the statement as shown in the following example Statements are considered part of the CREATE SCHEMA statement until a semicolon or an end of file symbol is reached CREATE SCHEMA AUTHORIZATION sarah CREATE TABLE mytable mytime DATE mytext TEXT GRANT SELECT UPDATE DELETE ON mytable TO rick CREATE VIEW myview AS SELECT FROM mytable WHERE mytime gt 12 31 1992 REATE INDEX idxtime ON mytable mytime Q Creating Objects Within CREATE SCHEMA All objects created by a CREATE SCHEMA statement are owned by user name even if you do not explicitly name each object If you are the DBA you can create objects for another user If you are not the DBA and you attempt to create something for an owner other than user name you receive an error Granting Privileges Within
557. total_price FROM items WHERE order_num 1013 SELECT COUNT FROM orders WHERE order_num 1001 SELECT MAX LENGTH fname LENGTH lname FROM customer If you use an aggregate function and one or more columns in the select list you must put all the column names that are not used as part of an aggregate or time expression in the GROUP BY clause 1 462 Syntax Expression Subset of Expressions Allowed in an Aggregate Expression The argument of an aggregate function cannot itself contain an aggregate function You cannot use the aggregate functions found in the following list MAX AVG order_num e An aggregate function in a WHERE clause unless it is contained in a subquery or if the aggregate is on a correlated column originating from a parent query and the WHERE clause is within a subquery that is within a HAVING clause e An aggregate function on a BYTE or TEXT column For the full syntax of an aggregate expression see page 1 430 Including or Excluding Duplicates in the Row Set The DISTINCT keyword causes the function to be applied to only unique values from the named column The UNIQUE keyword is a synonym for the DISTINCT keyword The ALL keyword is the opposite of the DISTINCT keyword If you specify the ALL keyword all the values selected from the named column or expression including any duplicate values are used in the calculation COUNT Keyword The COUNT keyword returns the nu
558. trail began immediately after you created the archive copy RECOVER TABLE customer DROP AUDIT FOR customer CREATE AUDIT FOR customer Third create a new backup of the recovered table The audit trail file is not in human readable form Even so it is possible for the DBA to copy the file to a database dat file and manipulate the file The modified file can be copied back to the audit trail file enabling customized restorations of particular tables For example you can modify the audit trail file to exclude rows entered by a particular user or to undo specific transac tions For specific instructions on modifying audit trail files refer to the manual for your application development tool References See the CREATE AUDIT and DROP AUDIT statements in this manual Syntax 1 293 RENAME COLUMN RENAME COLUMN Purpose Use the RENAME COLUMN statement to change the name of a column Syntax Table RENAME COLUMN Name old column TO ________ p 1 506 new column is the new name of the column table old column is the column you are renaming Usage You can rename a column of a table if any of the following conditions are true e You own the table e You have the DBA privilege on the database You have the Alter privilege on the table When you rename a column choose a column name that is unique within the table If the column is referenced by a view in the database the text of t
559. ts are returned to the program variables and the sqlcode variable is set to a negative value The name of the sqlcode variable for each product is shown in the following table Product Variable Name ESQL C sqlca sqlcode SQLCODE ESQL COBOL SQLCODE OF SQLCA WITH NO LOG Option If you use the WITH NO LOG keywords operations on the temporary table are not included in the transaction log operations You can use this option to reduce the overhead of transaction logging Syntax 1 343 SELECT UNION Operator Place the UNION operator between two SELECT statements to combine the queries into a single query You can string several SELECT statements together using the UNION operator Corresponding items do not need to have the same name Restrictions on a Combined SELECT Several restrictions apply on the queries that you can connect with a UNION operator as described in the following list e The number of items in the SELECT clause of each query must be the same and the corresponding items in each SELECT clause must have compatible data types e Ifyou use an ORDER BY clause it must follow the last SELECT clause and you must refer to the item ordered by integer not by identifier Ordering takes place after the set operation is complete e You cannot use a UNION operator inside a subquery or in the definition of a view e You cannot use an INTO clause in a query unless you are sure that the compound query returns exactly one
560. ts at a time You can execute a new PREPARE statement with an exist ing statement identifier if you wish to bind a given statement identifier to different SQL statement text PREPARE The PREPARE statement supports dynamic statement identifier names which allow you to prepare a statement identifier as an identifier or as a host char acter string variable In the following pairs of examples the first example shows a statement identifier prepared as an SQL API variable and the second shows it as a character string constant strcpy stmtid query2 exec sql prepare stmtid from select from customer exec sql prepare query2 from select from customer INFORMIX ESQL C MOVE QUERY_2 TO STMTID EXEC SQL PREPARE STMTID FRO SELECT FROM CUSTOMER END EXEC EXEC SQL PREPARE QUERY_2 FRO SELECT FROM CUSTOMER END EXEC INFORMIX ESQL COBOL A statement id variable must be of the CHARACTER data type In C it must be defined as char In COBOL id variables must be declared as a standard CHARACTER type Statement Text The PREPARE statement can take statement text either as a quoted string or as text stored in a program variable The following restrictions apply to the statement text e The text can contain only SQL statements It cannot contain statements or comments from the host programming language Comments preceded by two hyphens or enclosed in curly bra
561. ts file refer to the INFORMIX OnLine Administrator s Guide 1 54 Syntax CREATE AUDIT CREATE AUDIT Purpose Syntax Usage Use the CREATE AUDIT statement to create an audit trail file and to start writing the audit trail for an INFORMIX SE database EE CREATE AUDIT FOR janie Name IN pathname p 1 506 Synonym Name p 1 504 pathname specifies the full operating system pathname and file for the audit trail file You can create an audit trail to keep a record of all modifications to a table An audit trail is a complete history of all additions deletions and updates to the table The audit trail is used to reconstruct the table from a backup copy made at the time the audit trail is created You only can use the CREATE AUDIT statement with INFORMIX SE INFORMIX OnLine Dynamic Server provides for full database logging using log files You must own the table or have DBA status to use the CREATE AUDIT statement You must set Execute privilege for all directories below root in pathname for each class of user owner owner s group and public that accesses your database If an audit trail file with the same pathname already exists the CREATE AUDIT statement does nothing If an audit trail file for the same table exists with a different pathname an error message is returned Make a backup copy of your database files as soon as you run the CREATE AUDIT statement but before you make an
562. tual text of the procedure resides in a separate file Syntax EZM CREATE PROCEDURE FROM filename variable name filename is the name of the file or the name of the path and file that contains the full text of the CREATE PROCEDURE statement variable name is a program variable that holds the name of the file that contains the full text of the CREATE PROCEDURE statement Usage The filename provided in this statement is relative if a simple filename is provided the database server looks for the file in the current directory References 1 76 Syntax See the CREATE PROCEDURE statement in this manual In the Informix Guide to SQL Tutorial see the discussion of creating and using stored procedures in Chapter 11 CREATE SCHEMA CREATE SCHEMA Purpose The CREATE SCHEMA statement allows you to issue a block of CREATE and GRANT statements as a unit It allows you to specify an owner grantor of your choice for the subsequent block of CREATE and GRANT statements Syntax B CREATE SCHEMA _____ user CREATE TABLE AUTHORIZATION name C Site meni CREATE INDEX o Statement 7 p 1 62 CREATE VIEW Kd Statement p 1 136 CREATE SYNONYM Statement p 1 80 GRANT Koo Statement p 1 194 CREATE TRIGGER N Statement p 1 110 m CREATE OPTICAL o OP CLUSTER m Statement INFORMIX OnLine Optical User Manual user name is the name of the user
563. uch as INFORMIX ESQL C or the DB Access database access utility which is shipped as part of your database server The application development tool SQL API or DB Access enables you to compose queries send them to the database server and view the results that the database server returns You can use DB Access to try out all the SQL statements described in this guide Preface iii Summary of Chapters The Informix Guide to SQL Syntax includes the following chapters e This Preface provides general information about the book and lists additional reference materials that can help you understand relational database management The Introduction tells how SQL fits into the Informix family of products and books explains how to use this book introduces the demonstration database from which the product examples are drawn and lists the new features for Version 6 0 of Informix database server products Chapter 1 SQL Statements explains the workings of all the SQL statements supported by Informix products Detailed diagrams walk you through every clause of each SQL statement Thorough usage instruc tions pertinent examples and references to related material complete the SQL picture Chapter 2 SPL Statements presents all the detailed syntax diagrams and explanations for SPL statements Informix Welcomes Your Comments iv Preface A reader response card is provided with this manual Please use this card to
564. uffer is too full to hold the new row at the start of a PUT statement e A FLUSH statement executes ACLOSE statement closes the cursor e An OPEN statement executes naming the cursor When applied to an open cursor the OPEN statement closes the cursor before reopening it this implied CLOSE statement flushes the buffer A COMMIT WORK statement executes e The buffer contains blob data flushed after a single PUT If the program terminates without closing an insert cursor the buffer remains unflushed Rows inserted into the buffer since the last flush are lost Do not rely on the end of the program to close the cursor and flush the buffer Syntax 1 289 PUT Error Checking The sqlca contains information on the success of each PUT statement as well as information that lets you count the rows that were inserted The result of each PUT statement is contained in the fields of the sqlca as shown in the following table ESQL C ESQL COBOL sqlca sqlcode SQLCODE SQLCODE OF SQLCA sqlca sqlerrd 2 SQLERRDJ 3 OF SQLCA Data buffering with an insert cursor means that errors are not discovered until the buffer is flushed For example an input value that is incompatible with the data type of the column for which it is intended is discovered only when the buffer is flushed When an error is discovered rows in the buffer located after the error are not inserted they are lost from memory The SQLCODE field is set to zero if
565. up restore procedure for making archive copies of a database that includes audit trails is as described in the following list Execute the DROP AUDIT statement for each table that has an audit trail The DROP AUDIT statement ends system logging to the audit trail files Execute the CREATE AUDIT statement for each table specifying the pathname of the new audit trail For maximum protection specify a loca tion that is not on the same storage device as the database You can also select a filename that reflects the table name and the sequence of the file in the audit trail for example audit_cust_001 or audit_cust_002 The CREATE AUDIT statement registers the new name and location of the Table Name p 1 506 audit trail file in the systables system catalog table Back up the database files using an operating system utility RECOVER TABLE During execution the RECOVER TABLE statement checks that the audit trail and table name have consistent record numbers for rows where changes occurred In extremely rare instances the RECOVER TABLE statement can find an inconsistency caused by a system crash In this case only the RECOVER TABLE statement stops and you must restore the table manually The following list of actions and statements serves as a guide to recover the customer table First restore the customer table from your last archive copy Second run the following statements which assume that your audit
566. updates 10 33T Index 25 26 Index K Key lock 7 8T Keywords using in triggered action 1 123S Key candidate See Candidate key Key composite 8 23T Key foreign See Foreign key Key primary 8 22T Key primary See Primary key constraint Korn shell how to set environment variables 4 5R profile file 4 4R L Label 2 49T 3 48T LANG environment variable 1 16R 4 49R Language supplement for added NLS functionality 1 22R LAST keyword syntax in FETCH 1 1945 use in FETCH 1 196S Latency 13 17T LC_COLLATE environment variable 1 16R 4 50R LC_CTYPE environment variable 1 16R 4 51R LC_MONETARY environment variable 1 17R 4 52R LC_NUMERIC environment variable 1 17R 4 53R LC_TIME environment variable 1 17R 4 53R LENGTH field setting with SET DESCRIPTOR 1 357S with DATETIME and INTERVAL types 1 358S with DECIMAL and MONEY types 1 358S LENGTH function in expression 1 314S on TEXT 2 64T on VARCHAR 2 64T syntax in expression 1 443S 1 453S use in expression 1 4535 2 63T LET statement assigning values 14 21T executing a procedure 14 9T syntax 2 28S LIKE keyword syntax in Condition segment 1 405S use in SELECT 1 328S wildcard characters 1 328S LIKE keyword used to test for equality in WHERE clause 2 29T LIKE relational operator 2 37T LIKE test 13 32T Literal DATETIME in Condition segment 1 405S in expression 1 436S 1 441S segment 1 487S syntax 1 488S syntax in INSERT 1 250S use in ALTER TABLE 1 188
567. updates 4 22T in stored procedure syntax 14 7T inserting with a cursor 6 11T ISAM error code 5 12T using to identify NLS database server 1 19R ESCAPE keyword syntax in Condition segment 1 405S use in Condition segment 1 409S with LIKE keyword 1 328S 1 4115 with MATCHES keyword 1 329S 1 4125 with WHERE keyword 1 3285 2 43T ESQL cursor use 5 19T to 5 28T DELETE statement in 6 3T delimiting host variables 5 6T dynamic embedding 5 5T 5 28T error handling 5 16T fetching rows from cursor 5 21T host variable 5 6T 5 8T indicator variable 5 15T INSERT in 6 8T NLS errors in SQLERRM field 1 19R overview 5 3T to 5 37T 6 3T to 6 17T preprocessor 5 4T scroll cursor 5 23T selecting single rows 5 13T SQL Communications Area 5 8T SQLCODE 5 11T SQLERRD fields 5 12T static embedding 5 5T UPDATE in 6 14T Estimating blobpages 10 17T maximum number of extents 10 10T size of index 10 16T table size with fixed length rows 10 13T table size with variable length rows 10 14T Example database See Demonstration database EXCLUSIVE keyword syntax in DATABASE 1 140S in LOCK TABLE 1 260S use in DATABASE 1 1425 in LOCK TABLE 1 262S Exclusive lock 7 6T EXECUTE IMMEDIATE statement description of 5 34T restricted statement types 1 1915 syntax and usage 1 190S using with concatenation operator 1 4325 EXECUTE ON keywords syntax in GRANT 1 231S in REVOKE 1 300S use in GRANT 1 237S in REVOKE 1 300S EXECUTE PROCEDURE statement 1 1925 assign
568. using the standard UNIX authorization procedures for example checking the etc hosts equiv file Connecting to pre Version 6 0 INFORMIX OnLine Dynamic Servers The CONNECT statement syntax described in this chapter is valid for a Version 6 0 application connecting to pre Version 6 0 database servers As with Version 6 0 database servers an implicit connection can be made to a pre Version 6 0 server provided that no existing implicit connections exist and no implicit connections have been previously terminated You cannot connect to a pre Version 6 0 server from aVersion 6 0 application if the server is an INFORMIX SE server having nettype seipcpip Connections to pre Version 6 0 OnLine database server differ in the following respects The CLOSE DATABASE statement causes a connection to a pre Version 6 0 database server to be dropped The same statement applied to a Syntax 1 53 CONNECT connection to a Version 6 0 database server causes the database to close but the connection remains e Ifan application makes a connection to a pre Version 6 0 database server without using the WITH CONCURRENT TRANSACTION clause you must close the database effectively dropping the connection before switching to a different connection otherwise OnLine returns error 1801 References See the DISCONNECT SET CONNECT DATABASE START DATABASE and CREATE DATABASE statements in this manual For information on the contents of the sqlhos
569. ust TO NOT CLUSTER ALTER INDEX ix_ord TO CLUSTER Syntax 1 13 ALTER INDEX The first two statements create indexes for the orders table and cluster the physical table in ascending order on the customer_num column The last two statements recluster the physical table in ascending order on the order_num column References See the CREATE INDEX and CREATE TABLE statements in this chapter In the Informix Guide to SQL Tutorial see the discussion of clustered indexes in Chapter 10 1 14 Syntax ALTER TABLE ALTER TABLE Purpose Syntax Usage Use the ALTER TABLE statement to add a column to or delete a column from a table modify the data constraints placed on a column add a constraint to a column or a composite list of columns drop a constraint associated with a column or a composite list of columns or change the extent size Z Wa ALTER TABLE Table Name C ADD Clause p 1 506 p 1 17 N DROP Clause Kine p 126 p 1 504 oO N MODIFY Clause p 1 27 ADD CONSTRAINT Clause p 1 29 DROP CONSTRAINT Clause p 1 32 Bro MODIFY NEXT SIZE Clause p 1 33 8 gt LOCK MODE Clause p 1 33 You must own the table name have the DBA privilege or be granted the Alter privilege on the specified table to use the ALTER TABLE statement You can not alter a temporary table To add a referentia
570. ventions are used throughout this manual italics New terms emphasized words and variables are printed in italics boldface Database names table names column names filenames utilities and other similar terms are printed in boldface computer Information that the product displays and information that you enter are printed in a computer typeface KEYWORD All keywords appear in uppercase letters information that if ignored could cause harm to your This symbol indicates a warning Warnings provide critical A database Additionally when you are instructed to enter or execute text immediately press RETURN after the entry When you are instructed to type the text or press a key no RETURN is required Syntax Conventions Syntax diagrams describe the format of SQL statements or commands including alternative forms of a statement required and optional parts of the statement and so forth Syntax diagrams have their own conventions which are defined in detail and illustrated in this section SQL statements are listed in their entirety in Chapter 1 of this manual although some statements may appear in other manuals Introduction 5 How to Use This Manual 6 Introduction Each syntax diagram displays the sequences of required and optional elements that are valid in a statement or command Briefly e All keywords are shown in uppercase letters for ease of identification though you need not enter
571. vilege on the database The three database privileges are associated with the following keywords CONNECT RESOURCE DBA gives you the ability to query and modify data You can modify the database schema if you own the object you wish to modify Any user with the Connect privilege can perform the following functions Execute SELECT INSERT UPDATE and DELETE statements provided the user has the necessary table level privileges Create views provided the user has the Select privilege on the underlying tables Create synonyms Create temporary tables and create indexes on the temporary tables e Alter or drop a table or an index provided the user owns the table or index or has the Alter Index or References privilege on the table Grant privileges on a table provided the user owns the table or has been given privileges on the table with the WITH GRANT OPTION keyword gives you the ability to extend the structure of the database In addition to the capabilities of the Connect privilege the holder of the Resource privilege can perform the following functions Create new tables Create new indexes Create new procedures allows the holder of DBA privilege to perform the following functions in addition to the capabilities of the Resource privilege e Grant any privilege including the DBA privilege to another user Use the NEXT SIZE keyword to alter extent sizes in the system catalog
572. w 1 120S old 1 120S rules for 1 124S scope of 1 125S table of values 1 126S using 1 1245 when to use 1 125S COS function syntax in expression 1 4585 use in expression 1 459S COUNT DISTINCT clause 1 125S COUNT field getting contents with GET DESCRIPTOR 1 210S setting value for WHERE clause 1 354S use in GET DESCRIPTOR 1 212S COUNT function and GROUP BY 3 6T as aggregate function 2 53T count rows to delete 4 5T use in a subquery 4 6T use in expression 1 4635 1 465S with DISTINCT 2 54T COUNT keyword use in SET DESCRIPTOR 1 355S CREATE AUDIT statement need for archive 1 55S starts audit trail 1 55S syntax 1 55S CREATE DATABASE statement and dbspace 10 5T ANSI compliance 1 595 in command script 9 26T logging with OnLine 1 59S sets shared lock 7 6T SQLAWARN after 5 12T syntax 1 57S using with CREATE SCHEMA 1 775 INFORMIX SE 1 608 9 23T OnLine 9 21T PREPARE 1 585 CREATE INDEX statement composite indexes 1 655 implicit table locks 1 635 locks table 7 7T syntax 1 625 usin with CREATE SCHEMA 1 77S using with ASC keyword 1 66S CLUSTER keyword 1 64S DESC keyword 1 665 UNIQUE keyword 1 645 See also Index Name segment CREATE PROCEDURE FROM statement in embedded languages 14 5T syntax and use 1 765 CREATE PROCEDURE statement inside a CREATE PROCEDURE FROM 14 5T syntax 1 68S use of dbschema 5 34R using 14 5T CREATE SCHEMA statement defining a trigger 1 1115 syntax 1 778 with CREATE sequences 1 785 wit
573. we think documentation is very important After all manuals are an integral part of our product line Because documentation is important we want to know what you think about our manuals You can tell us by filling out and returning the Reader Response Card Thanks for your help 1 Overall how do you rate this manual Outstanding Very good Good C Average Poor 2 Is the manual effective e Is it organized so you can find things O Yes O No e Is the index adequate Yes No e Is the table of contents easy to use Yes No e If applicable do you find the statement syntax readable Yes No e Are topics presented in a useful sequence Yes No e Are the examples useful Yes No 3 What did you think of the level of description e Writing quality Very good Good Average CI Poor e Clarity Very clear Average Hard to understand Level Too technical Just right Oversimplified 4 When you need to find information quickly which part of the documentation do you use e Index Often Sometimes Rarely Never e Table of Contents Often Sometimes Rarely Never e Quick Reference Card Often Sometimes Rarely Never e Chapter summaries
574. wing trig gers on the items table trig3 is illegal because its column list includes stock_num which is a triggering column in trig1 CREATE TRIGGER trigl UPDATE OF item_num stock_num ON items REFERENCING OLD AS pre NEW AS post FOR EACH ROW EXECUTE PROCEDURE procl CREATE TRIGGER trig2 UPDATE OF manu_code ON items BEFORE EXECUTE PROCEDURE proc2 j Illegal trigger stock_num occurs in trigl CREATE TRIGGER trig3 UPDATE OF order_num stock_num ON items BEFORE EXECUTE PROCEDURE proc3 j Multiple update triggers on a table cannot include the same columns CREATE TRIGGER When an UPDATE Statement Activates Multiple Triggers When an UPDATE statement updates multiple columns that have different triggers the column numbers of the triggering columns determine the order of trigger execution Execution begins with the smallest triggering column number and proceeds in order to the largest triggering column number The following example shows that table taba has four columns a b c d CREATE TABLE taba a int b int c int d int Define trig1 as an update on columns a and c and define trig2 as an update on columns b and d as shown in the following example CREATE TRIGGER trigl UPDATE OF a c ON taba AFTER UPDATE tabb SET y y 1 CREATE TRIGGER trig2 UPDATE OF b d ON taba AFTER UPDATE tabb SET z z 1 The tri
575. with NLS activated 1 15R 2 25T with ORDER BY 2 14T See also ORDER BY keywords Space as delimiter in DATETIME 3 9R as delimiter in INTERVAL 3 15R Specifying ANSI compliance 1 11R SPL flow control statements 14 22T program variable 5 5T relation to SQL 14 3T See also Stored procedure SQL ANSI standard 1 15T cursor 5 19T description of 1 14T error handling 5 16T history 1 14T in NLS ready products 1 22R Informix SQL and ANSI SQL 1 15T interactive use 1 17T optimizing See Optimizer standardization 1 14T statement types 1 55 SQL Communications Area GSQLCA altered by end of transaction 6 5T description of 5 8T effect of setting DBANSIWARN 4 15R inserting rows 6 11T result after CLOSE 1 398 result after DATABASE 1 140S result after DESCRIBE 1 163S result after FETCH 1 202S result after FLUSH 1 204S result after OPEN 1 264S 1 265S result after PUT 1 290S result after SELECT 1 321S returning NLS error messages to 1 19R See also SQLAWARN SQLCODE and SQLERRD SQL DESCRIPTOR clause See DESCRIBE statement SQL Descriptor See SQL Communications Area SQLCA SQL statements FILE 5 23R INSERT 5 23R SQLAWARN array description of 5 12T syntax of naming 5 11T with PREPARE 5 30T sqlca record and EXECUTE statement 1 186S SQLCA See SQL Communications Area SQLCODE field after opening cursor 5 20T description of 5 11T end of data on SELECT only 6 14T end of data signalled 5 17T set by DELETE 6 4T set
576. with a plus or a minus sign Integers do not contain decimal points The following examples shows some integers 10 S2 25567 Syntax 1 493 Literal Number 1 494 Syntax Floating and decimal numbers contain a decimal point and or exponential notation The following examples show floating and decimal numbers 123 456 1 23456e2 123456 0e 3 When you use a literal number as a MONEY value do not precede it with a money symbol or include commas Procedure Name Procedure Name Purpose Syntax Usage Use the Procedure Name segment wherever you see a reference to a procedure name in a syntax drawing It appears in the following statements CREATE PROCEDURE DROP PROCEDURE EXECUTE PROCEDURE GRANT UPDATE Identifier p 1 469 owner owner MS database T dbservername database is the name of the database in which the procedure resides dbservername is the name of the INFORMIX OnLine Dynamic Server database server that is home to database The sign is a literal character that you must use to introduce the database server name owner is the user name of the owner of the procedure If you are using an ANSI compliant database you must use the owner convention for a procedure that you do not own If you use quotes owner appears exactly as typed The actual name of the procedure is an SQL identifier Syntax 1 495 Procedure Name If you are creating the procedure the n
577. without qualifiers If your variable uses another set of qualifiers you must provide the same qualifiers when you use CURRENT as the default value The following example defines a DATETIME variable with qualifiers and uses CURRENT with matching qualifiers DEFINE GLOBAL d_var DATETIME YEAR TO MONTH DEFAULT CURRENT YEAR TO MONTH TODAY If you use TODAY as the default the variable must be a DATE value TEXT and BYTE The only default value possible for a TEXT or BYTE variable is null The following example defines a global variable call 1_blob of type TEXT CREATE PROCEDURE use_text DEFINE i INT DEFINE GLOBAL 1_blob REFERENCES TEXT DEFAULT NULL END PROCEDURE Declaring Local Variables 2 12 SPL Statements Nonglobal local variables do not allow defaults The following example shows typical definitions of local variables CREATE PROCEDURE def_ex DEFINE i INT DEFINE word CHAR 15 DEFINE b_day DATE DEFINE c_name LIKE customer fname DEFINE b_text REFERENCES TEXT END PROCEDURE DEFINE Declaring Variables LIKE Columns If you use the LIKE clause variable name is defined as the same type as the type of the column in table The types of variables defined as database columns are resolved at run time therefore column and table do not exist at compile time Declaring Variables as the PROCEDURE Type The PROCEDURE type indicates that in the current scope
578. word implies a range operator the range is defined by left expression and right expression and the number of increments is set implicitly with the STEP increment expression option If you use the TO keyword the vari able name must be an INT or SMALLINT data type The following example shows two equivalent FOR statements Each uses the TO keyword to define a range The first statement uses the IN keyword and the second statement uses an equal sign Each statements causes the loop to execute five times FOR index_var IN 12 TO 21 STEP 2 statement block END FOR FOR index_var 12 TO 21 STEP 2 statement block END FOR If you omit the STEP option increment expression is given the value of 1 if right expression is less than left expression or 1 if right expression is more than left expression If the increment expression is specified it must be negative if right expression is less than left expression or positive if right expression is more than SPL Statements 2 17 FOR left expression The two statements in the following example are equivalent In the first statement the STEP increment is explicit In the second statement the STEP increment is implicitly 1 FOR index IN 12 TO 21 STEP 1 statement block END FOR FOR index 12 TO 21 statement block END FOR The value of variable name is initialized to the value of left expression In subsequent iterations increment expression is added to
579. word to update the current row of the active set of a cursor However you cannot update a row with a cursor if that row includes aggregates The cursor named in the CURRENT OF clause can only contain column names The UPDATE statement does not advance the cursor to the next row so the current row position remains unchanged You can restrict the effect of the CURRENT OF keyword if you associate the UPDATE statement with a cursor that was created with the FOR UPDATE keyword See the DECLARE statement on page 1 145 If the cursor was cre ated without specifying any columns for updating you can update any col umn in a subsequent UPDATE WHERE CURRENT OF statement However if the DECLARE statement that created the cursor specified one or more col umns in the FOR UPDATE clause you are restricted to updating only those columns in a subsequent UPDATE WHERE CURRENT OF statement The advantage to specifying columns in the FOR UPDATE clause of a DECLARE statement is speed INFORMIX SE and INFORMIX OnLine Dynamic Server can usually perform updates more quickly if columns are specified in the DECLARE statement The following INFORMIX ESQL C example illustrates the WHERE CURRENT OF form of the WHERE clause In this example updates are performed on a range of customers who receive 10 percent discounts assume that a new col umn discount is added to the customer table The UPDATE statement is pre pared outside the WHILE loop to ensure that parsing
580. wtab SET qty qty 2 WHERE s_num 5 AND mc ANZ In a database under INFORMIX SE all objects referenced in the triggered actions must be in the current database Syntax 1 133 CREATE TRIGGER Logging and Recovery 1 134 Syntax You can create triggers for databases with and without logging However when the database does not have logging you cannot rollback when the trig gering statement fails In this case it is your responsibility to maintain data integrity in the database In INFORMIX OnLine Dynamic Server if the trigger fails and the database has transactions all triggered actions and the triggering statement are rolled back because the triggered actions are an extension of the triggering statement The rest of the transaction however is not rolled back In INFORMIX SE if you explicitly begin a transaction you must explicitly roll back the whole transaction If the database has no transactions a possi bility exists that data integrity might be violated when the triggered actions fail Even if the database has logging any data definition statement in the triggered action cannot be rolled back Again it is your responsibility to maintain data integrity as well as integrity of the database structure Note that the row action of the triggering statement occurs before the triggered actions in the FOR EACH ROW section If the triggered action fails for a database without logging the application must restore
581. x 1 435 Expression Constant Expressions The possible syntax for constant expressions is shown in the following diagram Quoted gt N Strin gt p 1 497 USER SITENAME y A DBSERVERNAME Literal N Number A p 1 493 N TODAY A N CURRENT A DATETIME Field Qualifier p 1 428 Literal N DATETIME N p 1 487 Literal SK INTERVAL A p 1 490 Ne n UNITS datetime A unit datetime unit is one of the units that are used to specify an interval precision that is YEAR MONTH DAY HOUR MINUTE SEC OND or FRACTION if the unit is YEAR or the expression is a year month interval otherwise it is a day time interval n is a literal number comparable to the datetime unit that you choose 1 436 Syntax Expression The following examples show constant expressions DBSERVERNAME TODAY His first name is Q URRENT YEAR TO DAY INTERVAL 4 10 05 DAY TO MINUTE DATETIME 4 10 05 DAY TO MINUTE 5 UNITS YEAR The following list provides references for further information Quoted strings as expressions see Quoted String as an Expression on page 1 438 e The USER function in an expression see USER Function on page 1 438 The SITENAME and DBSERVERNAME functions in an expression refer to SITENAME and DBSERVERNAME Functions on page 1 438 e Literal numbers a
582. x in expression 1 462S use in expression 1 465S Symbol table 10 27T Synonym ANSI compliant naming 1 80S chaining 1 835 chains 12 18T creating with CREATE SYNONYM 1 805 difference from alias 1 80S dropping 1 177S in ANSI compliant database 1 14R synonym behavior in ANSI compliant database 1 14R Synonyms for table names 12 17T Syntax diagram conventions Intro 5S elements of Intro 9S sysdepend system catalog table 1 183S syssyntable 12 18T System catalog accessing 2 8R altering contents 2 9R character column data type when NLS activated 1 19R database entries 1 57S description of 2 3R map of tables 2 33R NCHAR columns in 1 19R privileges in 4 16T 11 9T querying 4 16T sysblobs 2 11R syschecks 2 11R syscolauth 2 12R 1 302S 11 9T syscoldepend 2 13R syscolumns 2 13R sysconstraints 2 16R sysdefaults 2 17R sysdepend 2 18R sysdistrib 2 18R sysindexes 2 20R sysopclstr 2 22R sysprocauth 2 23R sysprocbody 2 24R 14 8T sysprocedures 2 25R sysprocplan 2 26R sysreferences 2 26R syssynonyms 2 27R syssyntable 2 27R systabauth 2 28R 1 2395 1 302S 4 16T 11 9T systables 2 29R systrigbody 2 31R systriggers 2 32R sysusers 2 32R 11 9T sysviews 2 33R updating 2 9R updating statistics 2 9R used by optimizer 13 9T System catalog tables See System catalog System descriptor area 1 1645 assigning values to 1 354S modifying contents 1 3545 resizing 1 355S use with EXECUTE statement 1 187S System name in database name 1 42
583. xpression list must match the count and type of the corresponding variables in the variable list LET The following example shows several LET statements that assign values to procedure variables LET a ctd LET a b c d LET expire_dt end_dt 7 UNITS DAY LET name Brunhilda LET sname DBSERVERNAME LET this_day TODAY You cannot use multiple values to operate on other values For example the following statement is illegal LET a b c d 10 15 ILLEGAL EXPRESSION Using a SELECT Statement in a LET Statement Using a SELECT statement in a LET statement is equivalent to using a SELECT INTO procedure variable statement in a procedure The examples in this section use a SELECT statement in a LET statement You can use a SELECT statement to assign values to one or more variables on the left hand side of the operator as shown in the following example LET a b SELECT cl c2 FROM t WHERE id 1 LET a b c SELECT cl c2 FROM t WHERE id 1 15 You cannot use a SELECT statement to make multiple values operate on other values The code in the following example is illegal LET a b SELECT cl c2 FROM t 10 15 ILLEGAL CODE Because a LET statement is equivalent to a SELECT INTO statement the two statements in the following example have the same results a c and b d CREATE PROCEDURE proof DEFINE a b c d INT LET a b SELECT cl c2 FROM
584. y further changes to the database See the RECOVER TABLE statement for an example If possible put the audit trail file on a different physical device from the one that holds your data so that a failure of one does not damage the data on the other Syntax 1 55 CREATE AUDIT Audit trails slow your access to the database very slightly each alteration of the database is recorded in the audit trail file as well as in the database files The following example shows how to use the CREATE AUDIT statement in a UNIX environment CRI EATI E AUDIT FOR orders IN u safe orders aud References See the DROP AUDIT and RECOVER TABLE statements in this manual For more information on audit trails see the manual for your application development tool 1 56 Syntax CREATE DATABASE CREATE DATABASE Em Purpose Syntax CREATE DATABASE Usage Use the CREATE DATABASE statement to create a new database __ Database Namo N 1 421 is IN dbspace SE Log Clause OL Log Clause SE Log Clause WITH LOG IN pathname i 7 gt MODE ANSI OL Log Clause gt WITH LOG BUFFERED LOG MODE ANSI dbspace is the name of the dbspace in which you want to store the data for this database The dbspace must already exist pathname is the full pathname including the filename for the log file The database that you create becomes t
585. y to execute a DESCRIBE statement that uses one Only system descriptor areas that are allocated with the ALLOCATE DESCRIPTOR state ment can be used in a DESCRIBE statement in INFORMIX ESQL COBOL You can view the contents of the columns by executing a GET DESCRIPTOR state ment following a DESCRIBE statement on the specified system descriptor The following examples show the use of a system descriptor in a DESCRIBE statement in INFORMIX ESQL C and INFORMIX ESQL COBOL In the first example in each pair the descriptor is a quoted string in the second example in each pair it is an embedded variable name main exec sql allocate descriptor descl with max 3 exec sql prepare cursl FROM select from tab exec sql describe cursl using sql descriptor descl exec sql describe cursl using sql descriptor desclvar INFORMIX ESQL C Syntax 1 165 DESCRIBE EXEC SQL ALLOCATE DESCRIPTOR DESC1 WITH MAX 3 END EXEC EXEC SQL PREPARE CURS1 FROM SELECT FROM TAB END EXEC EXEC SQL DESCRIBE CURS1 USING SQL DESCRIPTOR DESC1 END EXEC EXEC SQL DESCRIBE CURS1 USING SQL DESCRIPTOR DESC1VAR END EXEC INFORMIX ESQL COBOL References See the ALLOCATE DESCRIPTOR DEALLOCATE DESCRIPTOR DECLARE EXE CUTE FETCH GET DESCRIPTOR OPEN PREPARE PUT and SET DESCRIPTOR statements in this manual for further information about using dynamic management statements In the Informix Guid
586. ym exists The following example reorganizes the items table The intent is to move the quantity column from the fifth position to the third The example illustrates four steps Create a new table new_table that contains the column quantity in the third position e Fill the table with data from the current items table Drop the old items table Rename new_table with the name items The following example reorganizes the items table using the RENAME TABLE statement CREATE TABLE new_table item_num SMALLINT order_num INTEGER quantity SMALLINT stock_num SMALLINT manu_code CHAR 3 total_price MONEY 8 INSERT INTO new_table SELECT item_num order_num quantity stock_num manu_code total_price FROM items DROP TABLE items RENAME TABLE new_table TO items You cannot use a ROLLBACK WORK statement to undo a RENAME TABLE statement that successfully executes If you roll back a transaction that con tains a RENAME TABLE statement the table retains its new name and you do not receive an error message Syntax 1 297 RENAME TABLE References See the ALTER TABLE CREATE TABLE DROP TABLE and RENAME COLUMN statements in this manual 1 298 Syntax REPAIR TABLE REPAIR TABLE Purpose Syntax Usage Use the REPAIR TABLE statement to remove and rebuild table indexes or data that may have been damaged or corrupted because of a power failure com puter crash or other unexp
587. ynonym In a network INFORMIX OnLine Dynamic Server verifies that the object of the synonym exists when you create the synonym The following example shows how to create a synonym for an object that is not in the current database CREATE SYNONYM mysum FOR payables phoenix jean summary The identifier mysum now refers to the table jean summary which is in the payables database on the phoenix database server Note that if the sum mary table is dropped from the payables database the mysum synonym is left intact Subsequent attempts to use mysum return a Table not found error Syntax 1 81 CREATE SYNONYM PUBLIC and PRIVATE Synonyms If you use the PUBLIC keyword or no keyword at all your synonym can be used by anyone who has access to the database If a synonym is public a user does not need to know the name of the owner of the synonym Any synonym in a database that is not ANSI compliant and was created before Version 5 0 of the database server is a public synonym Synonyms are always private If you use the PUBLIC or PRIVATE keywords you receive a syntax error If you use the PRIVATE keyword the synonym can be used only by the owner of the synonym or if the owner s name is specified explicitly with the syn onym There can be more than one private synonym with the same name in the same database However each synonym with that name must be owned by a different user You only can own one synonym with a given
588. you create a view with the following statement CREATE VIEW newcust AS SELECT fname lname FROM customer WHERE state NJ You BROWN can run the following SELECT statements on the view SELECT FROM brown newcust SELECT FROM newcust SELECT FROM systables WHERE tabname newcust AND owner USER In the first query in the preceding example the database server automati cally upshifts brown before the SELECT statement executes In the second query the database server returns the owner name BROWN already upshifted In the third query USER returns the login name as it is stored in this case in uppercase letters Table Name If you are the user nancy and you use the following statement the resulting view has the name NANCY njcust CREATE VIEW nancy njcust AS SELECT fname lname FROM customer WHERE state NJ If you are nancy and you use the following statement the resulting view has the name nancy njcust CREATE VIEW nancy njcust AS SELECT fname lname FROM customer WHERE state NJ The following SELECT statement fails because it tries to match the name NANCY njeust to the actual owner and table name of nancy njcust SELECT FROM nancy njcust References In the Informix Guide to SQL Tutorial see the discussion of owner naming in Chapter 13 Syntax 1 509 View Name View Name Purpose Use the View Name segment in the following sta
589. you modify a column all attributes previously associated with that column that is default value single column check constraint or referential constraint are dropped When you want certain attributes of the column to remain such as a primary key you must respecify those attributes For exam ple if you are changing the data type of an existing column quantity to SMALLINT and you want to keep the default value in this case 1 and non null attributes for that column you can issue the following ALTER TABLE statement ALTER TABLE items MODIFY quantity SMALLINT DEFAULT 1 NOT NULL Note Both attributes are specified again in the MODIFY clause Syntax 1 27 ALTER TABLE When you modify a column that has column constraints associated with it the following constraints are dropped e All single column constraints are dropped e All referential constraints that reference the column are dropped e If the modified column is part of a multiple column unique or primary key constraint all referential constraints that reference the multiple columns also are dropped For example if you modify a column that has a unique constraint the unique constraint is dropped If this column was referenced by columns in other tables those referential constraints are also dropped In addition if the col umn is part of a multiple column unique or primary key constraint the multiple column constraints are not dropped but any referen
590. z The server will search for the database in the usr xyz directory If an SE server in DBPATH does not have any directory path specified the server searches in the current directory if the server is local or the remote directory if the server is remote Syntax 1 51 CONNECT If a directory in DBPATH is an NFS mounted directory it is expanded to contain the hostname of the NFS machine and the complete pathname of the directory on the NFS host In this case the hostname must be listed in your sqlhosts file as a dbservername and an sqlexecd daemon must be running on the NES host USER Clause 1 52 Syntax USER Clause a USER auth variable user_id variable user identifier user identifier USING auth variable gt ae user_id a ia variable is an ESQL C or ESQL COBOL character type host variable that holds the valid password associated with user identifier The password must exist in the etc passwd file If the statement connects to a remote server the password must exist in the etc passwd file on both the local and remote servers is an ESQL C or ESQL COBOL character type host variable that stores a valid login name The user id variable must be listed in the etc passwd file If the statement connects to a remote server the user id variable must exist in the etc passwd file on both the local and remote servers If the USER clause is omitted in the CONNECT statement the current u

Informix Guide to SQL: Syntax, Version 6.0

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