Notes on Performing Cross-system SQL Operations

When you invoke an SQL statement using the ADDRESS SQL format, you can perform cross-system SQL operations.

Note the following:

In terms of return codes and the SQLCODE, there are no differences between local and cross-system SQL operations. However, if you specify SYSTEM(EXT) or SYSTEM(ALL), the value of SQLCODE is always 0. You must specify each specific system, and then check the value of SQLCODE if you need to perform validity checking. For more information, see Return Codes from ADDRESS SQL Instructions in this chapter.
When performing cross-system operations, error messages are sent to the external data queue.
If you want, you can use the ADDRESS OPSCTL host command environment to send an SQL command to a remote system. This example illustrates the usage of ADDRESS OPSCTL in conjunction with ADDRESS SQL (where sqlstatement is any valid SQL statement):
```
ADDRESS OPSCTL
  "MSF DEFAULT SYSTEM(SYS1) SYSWAIT(20)"
ADDRESS SQL
  "sqlstatement"
```
If you choose to use ADDRESS OPSCTL in this way, you may specify only one system name as the value for the SYSTEM keyword. For more information, see the AOF Rules User Guide.