Testing data/oracle database

I am looking for a suggested test scenario for testing the data in an oracle database for accuracy, which should include how to test updates to the database.

Explanation:
My company develops a software package that lays directly on top of oracle (sorry). One of our clients has asked us how we go about testing oracle to make sure that none of their data is missing. The data in the database remains static, so to say, we perform a monthly update to the database. Instead of saying: "Uh, er, test?" I have been asked to come up with something...however, I can't find anything in the ORACLE PRESS books that I have, I guess ORACLE doesn't need to be tested!!!

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JP Soria
Oracle7 DBA/Software Tester
Email: jpsoria_at_saxe.com
"Failing to plan = planning to fail"