The Challenge of Integrating Knowledge Representation and Databases

Two di erent aspects of data management are addressed by Knowledge Representation (KR) and Databases (DB): the semantic organization of data and powerful reasoning services by KR, and their e cient management and access by DB. It is recently emerging that experiences from both KR and DB should pro tably crossfertilize each other, and a great interest is rising about this topic. In particular, among several ways to approach knowledge representation, Description Logics (DL) are gaining, in the last years, a privileged place. In this paper, after brie y showing the importance of an integrated view of description logics and databases, our approach to this topic is presented. Our technique allows uniform access { by means of a DL-based query language { to information distributed over knowledge bases and databases. The separately existing retrieving functions of description logics management systems and of database management systems are integrated, in our extended paradigm, in order to allow, via a query language grounded on a DL-based schema knowledge, uniformly formulating and answering queries and, thus, uniform retrieval from mixed knowledge/data bases.