Abstract: EDBMS/2 is an engineering oriented database management system developed by our CAD Laboratory. This paper discusses one of its subsystems an deductive database management subsystem DEDBMS, and focuses on its user- interface, its workingflow and its functions. DEDBMS makes EDBMS/2 be able to deduce data and to process rules, so become a useful support software for integration and intellectualization of CAD/CAM systems.