HP Labs Technical Reports

Relations with Inherited Attributes

Litwin, Witold; Ketabchi, Mohammad; Risch, Tore



Abstract: Object Oriented Database Systems (OODBs) have demonstrated the utility of inheritance of data and methods. We propose enhancing the relation model with inheritance. The key ideas are relations (tables) in which some attributes are base attributes, while others are attributes inherited through predicates as in relational views. Such tables bridge the gap between base tables and views and become the basic data definition construct of a relational schema. The user benifits from semantically richer and more natural conceptual schemes. Queries and updates usually are formulated without logical navigation and referential integrity is implicit. Some view update problems are solved and versioning becomes easier. The inheritance predicates allow also for rules and for recursive tables that are a non-procedural solution to the common transitive closure and traversal recursion problems. Some of the proposed ideas should prove useful for OODBSs as well.

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