SQL Descriptor Area
The SQL descriptor area (SQLDA) is a dynamically allocated memory structure used to retrieve the result set from a dynamic cursor SELECT statement (where you do not know the identity of the columns ahead of time) or to specify the values for dynamic parameter markers. The SQLDA is composed of one instance of the SQLDA_T structure and multiple instances of the SQLDA_T structure as defined in the
proesql.h
header file in your ESQL installation directory.Following is the exact structure of the SQLDA:
Each SQLDA_T structure in the SQLDA provides storage for one column, or in the case of array columns, one array element in a dynamic result set. When used for dynamic parameter markers, each SQLDA_T structure provides storage for the value of one parameter marker in a prepared statement.
When retrieving data into your ESQL application, the SQLDA contains, for each column in the SELECT result, the necessary information to describe each column to your application, and also a pointer to the actual data returned when a row is fetched. The SQLDA handles one row at a time. When specifying the values for dynamic parameter markers, the SQLDA contains, for each parameter marker, the information to describe the value to Progress, and also a pointer to the actual data that Progress uses.
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