Approximate rewriting of queries using views

Afrati, F; Chandrachud, M; Chirkova, R; Mitra, P

dc.contributor.author	Afrati, F	en
dc.contributor.author	Chandrachud, M	en
dc.contributor.author	Chirkova, R	en
dc.contributor.author	Mitra, P	en
dc.date.accessioned	2014-03-01T02:45:58Z
dc.date.available	2014-03-01T02:45:58Z
dc.date.issued	2009	en
dc.identifier.issn	03029743	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/32491
dc.subject	Conjunctive Queries	en
dc.subject	Efficient Algorithm	en
dc.subject	Expressive Power	en
dc.subject	Search Space	en
dc.subject	Select Project Join	en
dc.subject.other	Conjunctive queries	en
dc.subject.other	Contained rewriting	en
dc.subject.other	Efficient algorithm	en
dc.subject.other	Expressive power	en
dc.subject.other	Literals	en
dc.subject.other	Search spaces	en
dc.subject.other	Select-project-join queries	en
dc.subject.other	Subgoals	en
dc.subject.other	Information systems	en
dc.subject.other	Query languages	en
dc.subject.other	Algorithms	en
dc.title	Approximate rewriting of queries using views	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1007/978-3-642-03973-7_13	en
heal.identifier.secondary	http://dx.doi.org/10.1007/978-3-642-03973-7_13	en
heal.publicationDate	2009	en
heal.abstract	We study approximate, that is contained and containing, rewritings of queries using views. We consider conjunctive queries with arithmetic comparisons (CQACs), which capture the full expressive power of SQL select-project-join queries. For contained rewritings, we present a sound and complete algorithm for constructing, for CQAC queries and views, a maximally-contained rewriting (MCR) whose all CQAC disjuncts have up to a predetermined number of view literals. For containing rewritings, we present a sound and efficient algorithm pruned-MiCR, which computes a CQAC containing rewriting that does not contain any other CQAC containing rewriting (i.e., computes a minimally containing rewriting, MiCR) and that has the minimum possible number of relational subgoals. As a result, the MiCR rewriting produced by our algorithm may be very efficient to execute. Both algorithms have good scalability and perform well in many practical cases, due to their extensive pruning of the search space, see [1]. © 2009 Springer.	en
heal.journalName	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)	en
dc.identifier.doi	10.1007/978-3-642-03973-7_13	en
dc.identifier.volume	5739 LNCS	en
dc.identifier.spage	164	en
dc.identifier.epage	178	en