Using subsumption for semantic query optimization
Domenico Beneventano, Sonia Bergamaschi, Stefano Lodi, Claudio Sartori · 1994
Semantic Query Optimization optimize query processing by transforming a query into a semantically equivalent one, i.e. a query whose result is the same for every instance of the database. Semantic query optimization can be obtained by a query rewriting that takes into account the integrity constraints the database must satisfy. In this paper we analyze the possibility of implementing semantic optimization in OODBMs by means of the subsumption relation computation over a database schema. Subsumption relations over a schema includes all the specialization relations between classes (types) both explicitly declared in the schema and entailed by the schema. Subsumption computation has been previously used in the database area to perform schemata acquisition and checking for coherence and query processing optimization. In this paper we extend complex object data models with integrity constraints expressed as rules and propose to apply subsumption computation to perform semantic query optimiz...