DLDB2: A Scalable Multi-perspective Semantic Web Repository

A true Semantic Web repository must scale both in terms of number of ontologies and quantity of data. It should also support reasoning using different points of view about the meanings and relationships of concepts and roles. Our DLDB2 system has these features. Our system is sound and complete on a sizable subset of Description Horn Logic when answering extensional conjunctive queries, but more importantly also computes many entailments from OWL DL. By delegating TBox reasoning to a DL reasoner, we focus on the design of the table schema, database views, and algorithms that achieve essential ABox reasoning over an RDBMS. We evaluate the system using synthetic benchmarks as well as real-world data and queries.