Locking

[Sudee]

Dear all, where should I go abt learning locking system? I have a system with a multiple user and sql as database. UI has a multi-layer(or parts) as many users can surf at a time. What I want to do is lock the user on different layers. What is the best way to achieve this? I am very begineer to this. Thank you. ====== You need a head to program. Cool, fast and sharp.