Method, system and program products for concurrent write access to a global data repository

One or more tables stored in a global data repository are concurrently accessible and modifiable. A client requests the locking of one or more tables within a global server data repository on behalf of a local tree. This locking creates a lock block, which enables at least a portion of the locked tables to be selected, modified and then merged back with the tables residing in the server. One or more other clients may also request to use the same lock block and thus, the same local tree, if shared concurrency is allowed. These other clients would also be allowed to select, modify and merge at least a portion of the tables. The merging of the tables is serialized at the global data repository, if necessary.