Derived objects and classes in DOOD systems

Toe closure property is essential to enhance the power of database languages. In the deductive object-oriented database (D00D) context, this property implies that the rule­derived objects as well as the rule-derived classes (i.e. the classes populated by the derived objects) be established wíth full 00 (object-oriented) features. This paper provídes methods to infer the 00 features of derived classes (i.e. the populations of derived classes and the class hierarchies including derived classes) from their deduction rules. Toe work is presented by a deductive language, called ERCLog, for an object and relationship data model. Toe principies of our methods can be applied to other D00D languages which distinguish the notions of schema and instance of databases