A model and its implentation in a practical CAD/CAM database

A practical CAC/CAM database system concept and a CAD specialized database are discussed. For conforming to practical design environments, the CAD/CAM database system is organized with three-layered databases, global, local and working databases. In this database organization, the working database which si a CAD specialized database id characterized by: - The information of a CAD data model based on the relational model, mixed with the network model to represent production-part structures; - Variable-length data manipulation to process non-structured data colection of unfixed number elements; - A vie mechanism to improve data independency; - FAst processing for designer-system interactions. From its comparison with the conventional relational and or CODASYL database systems, it has been seen that this system can manipulate a CAD database three to ten times as fast as these systems.