Rollback in forms

hi!
i want to know- upto what level can we rollback through forms- before Pre-Commit, or Post-Commit, or any other trigger? After which level we cant rollback?

Thanks and Regards,
Amit

In my mind you can use rollback in any triggers except POST-COMMIT.
This trigger fire after execution all POSTs for SQL statments and REAL database (not Forms) commit command.