If you have two identical sets of tables, for example YYYYYYYY.table1 and XXXXXXXX.table1 and want to test against both sets of tables, you can use the AUTHID preprocessor directive to switch which qualifier is used.
For example, if you set it to:
XDB(AUTHID=XXXXXXXX)
XXXXXXXX becomes the default qualifier. To run against both sets of data all you need to do is change the value of the AUTHID directive to YYYYYYYY and recompile. The next time you run your application you will be pointing to YYYYYYY.table1.