New Expressive Languages for Ontological Query Answering

Authors

  • Andrea Calì University of London, Birkbeck College
  • Georg Gottlob Oxford University
  • Andreas Pieris Oxford University

DOI:

https://doi.org/10.1609/aaai.v25i1.7957

Abstract

Ontology-based data access is a powerful form of extending database technology, where a classical extensional database (EDB) is enhanced by an ontology that generates new intensional knowledge which may contribute to answer a query. Recently, the Datalog+/- family of ontology languages was introduced; in Datalog+/-, rules are tuple-generating dependencies (TGDs), i.e., Datalog rules with the possibility of having existentially-quantified variables in the head. In this paper we introduce a novel Datalog+/- language, namely sticky sets of TGDs, which allows for a wide class of joins in the body, while enjoying at the same time a low query-answering complexity. We establish complexity results for answering conjunctive queries under sticky sets of TGDs, showing, in particular, that ontological conjunctive queries can be compiled into first-order and thus SQL queries over the given EDB instance. We also show some extensions of sticky sets of TGDs, and how functional dependencies and so-called negative constraints can be added to a sticky set of TGDs without increasing the complexity of query answering. Our language thus properly generalizes both classical database constraints and most widespread tractable description logics.

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Published

2011-08-04

How to Cite

Calì, A., Gottlob, G., & Pieris, A. (2011). New Expressive Languages for Ontological Query Answering. Proceedings of the AAAI Conference on Artificial Intelligence, 25(1), 1541-1546. https://doi.org/10.1609/aaai.v25i1.7957

Issue

Section

New Scientific and Technical Advances in Research