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Datalog+⁄−: A Family of Languages for Ontology Querying

Andrea Calì‚ Georg Gottlob‚ Thomas Lukasiewicz and Andreas Pieris

Abstract

In ontology-based data access, an extensional database is enhanced by an ontology that generates new intensional knowledge which has to be considered when answering queries. In this setting, tractable data complexity (i.e., complexity w.r.t. the data only) of query answering is crucial, given the need to deal with large data sets. This paper summarizes results on a recently introduced family of Datalog-based languages, called Datalog+/-, which is a new framework for tractable ontology querying. Plain Datalog is extended by allowing existential quantifiers, the equality predicate, and the truth constant false to appear in rule heads. At the same time, the resulting language is syntactically restricted, so as to achieve decidability and even tractability.

Book Title
Datalog Reloaded − 1st International Workshop‚ Datalog 2010‚ Oxford‚ UK‚ March 16−19‚ 2010. Revised Selected Papers
Editor
Oege de Moor and Georg Gottlob and Tim Furche and Andrew Jon Sellers
ISBN
978−3−642−24205−2
Pages
351−368
Publisher
Springer
Series
Lecture Notes in Computer Science
Volume
6702
Year
2011