Efficient data management is crucial to the success of a CAD/CAM system. Traditional database systems, designed to deal with only regular and structural data, cannot efficiently manage design data. In this paper, we present a data manager called EDBMS/2, which has been developed by our laboratory for engineering support applications. EDBMS/2 has a data model that combines features of both relational and semantic ones and owns flexible abilities for modeling engineering data, such as variable-length data processing, integrated management of structured data and unstructured data, and composite object handling. Mechanisms based on DBV and DBV graph concepts, proposed in EDBMS/2, make EDBMS/2 own powerful abilities for version management and run efficiently. By now, EDBMS/2 has been used successfully in EDCADS (integrated Electronic Devices CAD environment) project and as a lower level support to develop an object-oriented DBMS for mechanical engineering.