Abstract : We address the issue of Ontology-Based Data Access which consists of exploiting the semantics expressed in ontologies while querying data. Ontologies are represented in the framework of existential rules, also known as Datalog+/-. We focus on the backward chaining paradigm, which involves rewriting the query (assumed to be a conjunctive query, CQ) into a set of CQs (seen as a union of CQs). The proposed algorithm accepts any set of existential rules as input and stops for so-called finite unification sets of rules (fus). The rewriting step relies on a graph notion, called a piece, which allows to identify subsets of atoms from the query that must be processed together. We first show that our rewriting method computes a minimal set of CQs when this set is finite, i.e., the set of rules is a fus. We then focus on optimizing the rewriting step. First experiments are reported in the associated technical report.
https://hal-lirmm.ccsd.cnrs.fr/lirmm-00838791
Contributor : Mélanie König
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Submitted on : Wednesday, June 26, 2013 - 3:41:37 PM
Last modification on : Tuesday, June 25, 2019 - 1:25:57 AM
Long-term archiving on : Wednesday, April 5, 2017 - 4:38:57 AM
Mélanie König, Michel Leclère, Marie-Laure Mugnier, Michaël Thomazo. Sound, Complete, and Minimal Query Rewriting for Existential Rules. IJCAI: International Joint Conference on Artificial Intelligence, Aug 2013, Beijing, China. ⟨lirmm-00838791⟩
