Data bases for CAD applications

The characteristics of CAD data and the possibilities offered by database management systems with different data models are described. A classification of databases according to their data models is presented, and the different data models are compared. The semantic data models allow a higher abstraction level but the overhead cost involved in implementing these abstraction mechanisms may not be acceptable for finite-element applications. The object-oriented model, despite the many possibilities offered, has not attained sufficient stability for widespread use. A solution consisting of extending a classical data model to take into account the more important CAD data characteristics is proposed