Semantic Query Optimization by Subsumption in OODB
Domenico Beneventano, Sonia Bergamaschi, Claudio Sartori · 1996
: The purpose of semantic query optimization is to use semantic knowledge (e.g. integrity constraints) for transforming a query into a form that may be answered more efficiently than the original version. This paper proposes a general method for semantic query optimization in the framework of Object Oriented Database Systems. The method is applicable to the class of conjunctive queries and is based on two ingredients: a formalism able to express both class descriptions and integrity constraints rules as types; subsumption computation between types to evaluate the logical implications expressed by integrity constraints rules. 1 Introduction The purpose of semantic query optimization is to transform a query into an equivalent one that may be answered more efficiently than the original version. The basic idea is to use semantic knowledge about the database to transform the query. Informally, semantic equivalence means that the transformed query has the same answer as the original query o...