I want to lock record ( Update, Delete ) By certain date condition using DB Trigger. Means, If a user want to update data for previous months, He is unable to update or delete those data. I'm using Oracle 8.0.5
OK, so - where's the problem? You already described the problem - obviously, you know WHAT to do. HOW (syntax of trigger creation) can be found in any PL/SQL book (some samples are given in thread you read).
Do post the trigger code you wrote and explain what kind of problems you met during compilation / testing session so that we could help you further.
Unless, of course, you expect some of the Forum users to write it for you ...