To build an interface between product design and manufacturing execution modules is the first phase to achieving Computer Integrated Manufacturing for the factory of the future. A model of the Computer Aided Design (CAD)/Manufacturing Resource Planning (MRP II) integrated system, detailing the logical interaction between the systems in the areas of part specification maintenance, product structure data maintenance, and engineering changes, has been developed. An expert system based on multi-database interoperability, which uses a formal language, called "Update Dependencies", based on an AI production system, is being developed, and has been tested against the major part of the model design specification.