When you invoke a CSP, the DB2 access service creates a SQL statement that returns a result set that matches, as closely as possible, the Microsoft ODBC 2.0 specification results. For detailed information about the Microsoft ODBC 2.0 specification, see the Microsoft ODBC 2.0 Programmer’s Reference and SDK Guide.
Because the DB2 system catalog is significantly different from the ODBC specification, an exact match is impossible. To make the results match, the DB2 access service performs additional computations as it returns the rows. In some cases, the SQL statement is quite complex and must assemble the requested information from multiple sources.
In a few cases, such as sp_stored_procedures, sp_sproc_columns, and sp_server_info, information is stored in tables that were created during installation of DirectConnect.
Some information is static, depending upon the version of DB2 you are using. In these cases, the DB2 access service uses memory tables to improve the speed of operation. The following CSPs and system procedures use memory tables:
sp_capabilities
sp_datatype_info
sp_helpserver
sp_sqlgetinfo
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