Progress
Embedded SQL-92
Guide and Reference
DESCRIBE SELECT LIST Statement
Specifies that the DESCRIBE statement should write information about select list items in a prepared SELECT statement to an output SQLDA structure. Select list items are column names and expressions in a SELECT statement. A FETCH statement writes the values returned by a SELECT statement to the addresses stored in an output SQLDA.
A DESCRIBE SELECT LIST statement writes the number of select list items to the
sqld_nvars
field of an output SQLDA. If thesqld_size
field of the SQLDA is not equal to or greater than this number, DESCRIBE writes the value as a negative number tosqld_nvars
. Design your application to checksqld_nvars
for a negative number to determine if a particular output SQLDA is large enough to process the current SELECT statement.Design your application to issue a DESCRIBE SELECT LIST statement after the DECLARE CURSOR, PREPARE, and OPEN statements for a dynamic SELECT statement, but before the first corresponding FETCH statement for the cursor.
This is the syntax for a DESCRIBE SELECT LIST statement:
SYNTAX
statement_name
The name of a SELECT statement to be processed using dynamic SQL-92 steps. Typically, this is the same statement_name as in the PREPARE statement.
output_sqlda_name
The name of the SQLDA structure to which DESCRIBE will write information about select list items.
AUTHORIZATION
None
SQL COMPLIANCE
SQL-92
ENVIRONMENT
Embedded SQL-92 only
RELATED STATEMENTS
PREPARE Statement, DECLARE CURSOR Statement, OPEN Statement, FETCH Statement, CLOSE Statement, DESCRIBE BIND VARIABLES Statement
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