I am working on a previously installed zen cart. The installer has called on me to fix a database issue. I'm not sure how it happened, but the state data for all currently existing users is bogus data. This creates a problem when existing users log in and want to buy something. I need to update about 6000 users' state field in the database.

My question is this. Is there any way to run a simple script when a user logs in in order to force them to verify their state if the database contains bad information? I think this would fix the problem, however Ive never worked with zen cart before and I am not sure how to cleanly run a script on login. I would appreciate all suggestions, as well as information about looking a script to login.

Thanks