An apparatus and method provide virtual memory mapping and transaction management in an object-oriented database system having a database for permanently storing data, a cache memory for temporarily storing data, and a processing unit which runs application programs which request data using virtual addresses. The system performs data transfers in response to memory faults resulting from requested data not being available at specified virtual addresses and performs mapping of data in cache memory. The database includes pointers containing persistent addresses, which pointers are relocated between persistent addresses and virtual addresses. When a data request is made, either for read or write, from a client computer in a system, other client computers in the system are queried to determine if the requested data is cached and/or locked in a manner inconsistent with the requested use, and the inconsistent caching is downgraded or the transfer delayed until such downgrading can be performed.