If you have a record version number field in the table then you can read it for the record of interest. When you go to update the record you specify the expected version number in the update equivalent to the SQL WHERE along with the field id so if the version number has been incremented by another user update, your update will fail because the WHERE version=x part of the update will not match.
I think this depends on the database you use as well. I thought most modern databases apply a read lock while you are looking at a record and if you try to update the lock is upgraded to a write lock and if someone else beat you to the update an error is thrown. You would need to check your database documentation looks for pessimistic vs optimistic locking or just locking.
