Description logics for semantic query optimization in object-oriented database systems Domenico Beneventano, Sonia Bergamaschi, and Claudio Sartori   View Paper (PDF)   Return to March 2003, Volume 28, Number 1 Abstract Semantic query optimization uses semantic knowledge (i.e., integrity constraints) to transform a query into an equivalent one that may be answered more efficiently. This article proposes a general method for semantic query optimization in the framework of Object-Oriented Database Systems. The method is effective for a large class of queries, including conjunctive recursive queries ex- pressed with regular path expressions and is based on three ingredients. The first is a Description Logic, ODLRE, providing a type system capable of expressing: class descriptions, queries, views, in- tegrity constraint rules and inference techniques, such as incoherence detection and subsumption computation. The second is a semantic expansion function for queries, which incorporates restric- tions logically implied by the query and the schema (classes C rules) in one query. The third is an optimal rewriting method of a query with respect to the schema classes that rewrites a query into an equivalent one, by determining more specialized classes to be accessed and by reducing the num- ber of factors. We implemented the method in a tool providing an ODMG-compliant interface that allows a full interaction with OQL queries, wrapping underlying Description Logic representation and techniques to the user. ©2004 Association for Computing Machinery