record locking in flex or zend amf

How do you handle record locking in a flex (flash builder 4) application with multiple users?

It is using zend amf to talk to a database (mongodb or mysql).

For example, if user 1 loads a client reco开发者_如何学Pythonrd for edit and user 2 loads the same client record for edit, there is going to be data lost if user 1 saves their edit and then user 2 saves their edit - not knowing user 1 was editing.

I suppose I could implement my own system by having a lock flag or lock table and when a record is opened, check for lock / set the lock. However I am hoping there is already something people use to do this that is tested / proven.