Advanced Processing for Ontological Queries

13 years 2 months ago

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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. The ontological integrity constraints for generating this intensional knowledge can be speciﬁed in description logics such as DL-Lite. It was recently shown that these formalisms allow for very eﬃcient query-answering. They are, however, too weak to express simple and useful integrity constraints that involve joins. In this paper we introduce a more expressive formalism that takes joins into account, while still enjoying the same low query-answering complexity. In our framework, ontological constraints are expressed by sets of rules that are so-called tuple-generating dependencies (TGDs). We propose the language of sticky sets of TGDs, which are sets of TGDs with a restriction on multiple occurrences of variables (including joins) in the rule bodies. W...

Andrea Calì, Georg Gottlob, Andreas Pieris

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