On the Interaction of Existential Rules and Equality Constraints in Ontology Querying

Andrea Calì, Georg Gottlob, Giorgio Orsi, Andreas Pieris

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Ontological query processing is an exciting research topic in database theory, knowledge representation, and logic programming. In many cases, ontological constraints are expressed over an extensional database by extending traditional Datalog rules to allow existential quantification and equality atoms in the head. The unrestricted use of these features causes undecidability of query answering and, therefore, their interaction must be controlled. This work provides a tutorial-like introduction to the problem of query answering under existential and equality constraints. We survey the most notable (semantic and syntactic) restrictions to such constraints ensuring decidability of query answering, and we discuss their practical application to conceptual modelling.
Original languageEnglish
Title of host publicationCorrect Reasoning - Essays on Logic-Based AI in Honour of Vladimir Lifschitz
PublisherSpringer Berlin Heidelberg
Number of pages17
ISBN (Electronic)978-3-642-30743-0
ISBN (Print)978-3-642-30742-3
Publication statusPublished - 2012

Publication series

NameLecture Notes in Computer Science
PublisherSpringer Berlin Heidelberg
ISSN (Print)0302-9743


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