Abstract: An apparatus and method are provided for virtual memory mapping and transaction management in an object-oriented database system having permanent storage for storing data in at least one database, at least one cache memory for temporarily storing data, and a processing unit which runs application programs which request data using virtual addresses. When a data request is made, either for read or write, from a given 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.