Modifying system tables

I am developing a database of all the permissions of my users to each database that they use. This way I can determine what permissions that each user has and keep access to certain databases very secure by revoking everyone else. I was wondering what harm or side effects could be had if I directly modify the tables: sysusers, systabauth, syscolauth. What I want to do is revoke all priviledges from everyone and then grant only those permissions that are needed. This is the next stage in implementation and I just want to make sure that I can't mess anything up. Thanks, |======================================================================| | Travis Rayhons trvsryhn@cc.dordt.edu | | Dordt College Computer Services Programmer | |======================================================================|