Release 10.1A: OpenEdge Data Management:
SQL Reference

DESCRIBE

Writes information about a prepared statement to the SQL Descriptor Area (SQLDA). You use a DESCRIBE statement in a series of steps that allows a program to accept SQL statements at run time. Dynamically generated statements are not part of a program's source code; they are generated at run time.

There are two forms of the DESCRIBE statement:

The DESCRIBE BIND VARIABLES statement writes information about input variables in an expression to an SQLDA. These variables can be substitution variable names or parameter markers.
The DESCRIBE SELECT LIST statement writes information about select list items in a prepared SELECT statement to an SQLDA.

Syntax

DESCRIBE [ BIND VARIABLES | SELECT LIST ] FOR statement_name    INTO input_sqlda_name ;

The SQLDA is a host language data structure used in dynamic SQL processing. DESCRIBE statements write information about the number, data types, and sizes of input variables or select list items to SQLDA structures. Program logic then processes that information to allocate storage. OPEN, EXECUTE, and FETCH statements read the SQLDA structures for the addresses of the allocated storage.