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DEALLOCATE COLLECTION

Use the DEALLOCATE COLLECTION statement to release memory for a collection variable that was previously allocated with the ALLOCATE COLLECTION statement. Only Dynamic Server supports this statement, which is an extension to the ANSI/ISO standard for SQL. Use this statement with ESQL/C.

Syntax

Read syntax diagramSkip visual syntax diagram>>-DEALLOCATE COLLECTION--:variable----------------------------><
 
Element Description Restrictions Syntax
variable Name that identifies a typed or untyped collection variable for which to deallocate memory Must be the name of an ESQL/C collection variable that has already been allocated Name must conform to language-specific rules for names of variables

Usage

The DEALLOCATE COLLECTION statement frees all the memory that is associated with the ESQL/C collection variable that variable identifies. You must explicitly release memory resources for a collection variable with DEALLOCATE COLLECTION. Otherwise, deallocation occurs automatically at the end of the program.

The DEALLOCATE COLLECTION statement releases resources for both typed and untyped collection variables.

Tip:
The DEALLOCATE COLLECTION statement deallocates memory for an ESQL/C collection variable only. To deallocate memory for an ESQL/C row variable, use the DEALLOCATE ROW statement.

If you deallocate a nonexistent collection variable or a variable that is not an ESQL/C collection variable, an error results. Once you deallocate a collection variable, you can use the ALLOCATE COLLECTION to reallocate resources and you can then reuse a collection variable.

This example shows how to deallocate resources with the DEALLOCATE COLLECTION statement for the untyped collection variable, a_set:

EXEC SQL BEGIN DECLARE SECTION;
   client collection a_set;
EXEC SQL END DECLARE SECTION;
. . .
EXEC SQL allocate collection :a_set;
. . .
EXEC SQL deallocate collection :a_set;

Related Information

Related example: refer to the collection variable example in PUT .

Related statements: ALLOCATE COLLECTION and DEALLOCATE ROW

For a discussion of collection data types, see the IBM Informix ESQL/C Programmer's Manual.

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