Come on Lucy, did you at least try a search?
I’ve found:
- Here on B
B’s Download section you can find Steve Krandel’s presentation Using Designer to Implement Row-Level Security to get you started. - Row Level Security - Universe level
- Row Level Security (Best Practices ?)
- security question
- row level security - how to ?
And my recommendation (Oracle VPD e.g.) Object Level Security
Andreas 
(BOB member since 2002-06-20)