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Authordc.contributor.authorBarceló Baeza, Pablo 
Authordc.contributor.authorPieris, Andreas 
Authordc.contributor.authorRomero, Miguel 
Cita de ítemdc.identifier.citationSIGMOD Record, June 2017 (Vol. 46, No. 2)es_ES
Abstractdc.description.abstractThis paper reports on recent advances in semantic query optimization. We focus on the core class of conjunctive queries (CQs). Since CQ evaluation is NP-complete, a long line of research has concentrated on identifying fragments of CQs that can be efficiently evaluated. One of the most general such restrictions corresponds to bounded generalized hypertreewidth, which extends the notion of acyclicity. Here we discuss the problem of reformulating a CQ into one of bounded generalized hypertreewidth. Furthermore, we study whether knowing that such a reformulation exists alleviates the cost of CQ evaluation. In case a CQ cannot be reformulated as one of bounded generalized hypertreewidth, we discuss how it can be approximated in an optimal way. All the above issues are examined both for the constraint-free case, and the case where constraints, in fact, tuple-generating and equality-generating dependencies, are present.es_ES
Patrocinadordc.description.sponsorshipMillennium Nucleus Center for Semantic Web Research NC120004 EPSRC Programme EP/M025268/es_ES
Publisherdc.publisherAssociation for Computing Machineryes_ES
Type of licensedc.rightsAttribution-NonCommercial-NoDerivs 3.0 Chile*
Link to Licensedc.rights.uri*
Sourcedc.sourceSIGMOD Recordes_ES
Títulodc.titleSemantic optimization in tractable classes of conjunctive querieses_ES
Document typedc.typeArtículo de revista
Indexationuchile.indexArtículo de publicación ISIes_ES

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Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 3.0 Chile