I have a problem which I'm sure many of you must have dealt with.

I have the problem where two users can open the same record at about the
same time, one user could then update the record and then the other user
could also update the record. The first user's changes will be lost or
overwritten by the second user.

What I would like to happen is that the changes by the second user are
rejected, or at the very least they are given a warning to say that this
record has been updated since they opened it and do they want to go ahead
with their changes.

How do I do this? Can this be controlled through transactions?

Stephen