Please provide more detail about how updates will be handled to the database so I can give you a better answer. For example, what is the threshold for accuracy? If you want 100% accuracy you must check each field in each row 1-by-1.
If there is a “low” risk that other applications would modify the data. You can start with a simply boolean flag (IsChanged = ?) to sync 2 databases. But if you are going to sync multiple databases to a centeralized master copy then you need something more elaborate.
Tell me more about the problem…