On (In)Tractability of OBDA with OWL 2 QL

We show that, although conjunctive queries over OWL 2 QL ontologies are reducible to database queries, no algorithm can construct such a reduction in polynomial time without changing the data. On the other hand, we give a polynomial reduction for OWL 2 QL ontologies without role inclusions.

• Type: Journal
• Year: 2011
• Where: DLOG
• Authors: Stanislav Kikot, Roman Kontchakov, Michael Zakharyaschev
• Keywords: Automated Reasoning, Conjunctive Queries, Database Queries, DLOG 2011, Polynomial Time