Semantic query optimization for object queries

Abstract

Semantic query optimization is an approach to query optimization that utilizes semantic knowledge to reformulate a query into one that would generate the same set of answers in a more efficient way. The semantic query optimization becomes more important in OODB systems where object queries are complex due to the presence of object-oriented concepts such as subclassing relationship, referential relationship, and object-identifier. In this paper we investigate the representation of semantic constraints and present a semantic query optimization technique for object queries. This paper describes useful semantic transformation heuristics in object-oriented context. Using an object query optimizer prototype MagicVol, we conduct preliminary optimization experiments to verify that the semantic query optimization for object queries is reasonable and useful.