Optimistic Vs. Pessimistic Locking

I am confused, I'll admit that outright.

A lot of entries in these forums recommend optimistic locking for most cases. Well, I have a very simple case (like everyone else, I bet :-)) and it seems to me pessimistic locking is the right answer:

User A loads an item on screen for maintenance. When user B wants to load the same item on screen for maintenance, he/she should be presented with a message "Item in use by someone else". That way they know they can't perform maintenance on the item (as yet). This can be achieved with pessimistic locking, by locking the row that is being loaded for maintenance and only unlocking it after an update or after another item is loaded in maintenance. The lock would be in update mode. This way the record cannot be modified but queries (for reporting or lists) in other parts of the system would still work fine.

The alternative in this case would be to allow both users to load the item on screen for maintenance, allow both of them to make changes and allow both of them to save -- one of them will save, the other would be stopped and another message will pop up, "Item already changed". This can be acheived with optimistic locking, by just allowing the engine to do its job.

While both approaches work, I strongly consider the first one to be more user friendly. Noone looses any changes they made, they know they have to wait for the item to become available and everything's peachy (granted, loading the item on screen and then leaving for an extended lunch may trigger some unpleasant after effects :-)).

Apart from the pessimistic update mode lock in the first case, is there any other (read better, safer, recommended) way to achieve this?



Thank you,