Abstract: A database synchronizing system comprises a first subsystem and several second subsystems. The first subsystem comprises a first database. Each of the second subsystems comprises a second database, a data retrieving module, and a data merging module. The data retrieving module executes an updating request procedure to receive the data in the first database from the first subsystem. The data merging module synchronizes the data in the first database and the second databases with a merging method. The merging method comprises an inserting step, a deleting step, and an updating step.

Abstract: A system for distributed concurrent version management. The system includes a first server, a second server, and a first client. The first server has a first database including a file. The second server has a second database including a file copy corresponding to the file, a data replication module, and a connection detection module. When the first client wants to replace the file copy in the second server with an updated file, the file copy is replaced by the updated file when the first server and the second server are connected. Then, the updated file is copied to the first server by the data replication module, and the file in the first database is replaced by the updated file.