> Can't they put in a where condition in the update double checking that
> the locked_by is null?

Sure, but what if it was unlocked already by a user, then it will
overwrite the changes without even knowing there were changes.

Martijn Tonies
Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle &
MS SQL Server
Upscene Productions
http://www.upscene.com
My thoughts:
http://blog.upscene.com/martijn/
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