I am developing an application based on JBoss + MySQL with enabled transactions. This application will be deployed on 5 remote places. On another place there will be server which should keep an updated copy of each of the 5 databases. Once a day the personnel on each of the five places will dial-in the Internet and press a button to update the copy of it's database on the central server. I don't want to copy the entire database every time but just to send the updates.
I would be very grateful if you help me find the best solution.