DB2 REXX SQL for VM/ESA^(R): Installation and Reference

Appendix I. RXSQL Subcommand Environment

DB2 RXSQL commands may be executed in either the EXECSQL or RXSQL subcommand environment. The default environment may be altered (between various subcommand environments or the host environment) using the ADDRESS command. If ADDRESS EXECSQL or ADDRESS RXSQL has been invoked, you may code requests without the prefix 'EXECSQL' or 'RXSQL' respectively.

The command is passed directly to DB2 RXSQL without the search for EXECs or CP commands. Judicious use of either subcommand environment will improve the performance of a DB2 RXSQL application.

Do the following to invoke the DB2 RXSQL subcommand environment:

1. 'ADDRESS COMMAND' may be issued first to eliminate the CMS search for EXECs and CP commands.
2. DB2 RXSQL must first be invoked with a regular DB2 RXSQL command to load DB2 RXSQL as a nucleus extension and set up the subcommand environment. This command may request a harmless process such as setting tracing off for all modules or getting the names of all cursors used. Alternatively, the first command may do something relevant to your EXEC processing.
3. The 'ADDRESS EXECSQL' or 'ADDRESS RXSQL' command may be issued after the first DB2 RXSQL command. All non-REXX commands following this ADDRESS command are assumed to be EXECSQL or RXSQL subcommands and will be passed on to DB2 RXSQL.
4. It is assumed that the invocation of your DB2 RXSQL request is the same as the subcommand environment you are in unless you override it. For example, if your program issues 'ADDRESS EXECSQL',
   • any command that begins with the keyword EXECSQL, or does not have a keyword RXSQL, is processed using EXECSQL invocation rules.
   • any command that begins with the keyword RXSQL is processed using RXSQL invocation rules.

   If you wish to execute CMS or other non-RXSQL commands, another ADDRESS command must be issued. For more information on the use of ADDRESS, see the VM/ESA REXX/VM Reference manual.