Reserving object at database

I want an item unchanged when a user is busy with that item. How can I prevent other users to make a change with an object in the period of time when one user retrieves it and busy with a process to change it.
1 answers

The technique you are looking for is pessimistic record locking. Mendix by default uses optimistic locking. Here is a forum question answering your needs: even having a sample app for you: