Rewriting queries using views in the presence of arithmetic comparisons

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dc.contributor.author Afrati, F en
dc.contributor.author Li, C en
dc.contributor.author Mitra, P en
dc.date.accessioned 2014-03-01T01:25:05Z
dc.date.available 2014-03-01T01:25:05Z
dc.date.issued 2006 en
dc.identifier.issn 0304-3975 en
dc.identifier.uri http://hdl.handle.net/123456789/17534
dc.subject Databases en
dc.subject Query languages en
dc.subject Query rewriting en
dc.subject.classification Computer Science, Theory & Methods en
dc.subject.other Algebra en
dc.subject.other Algorithms en
dc.subject.other Computer programming en
dc.subject.other Database systems en
dc.subject.other Problem solving en
dc.subject.other Arithmetic comparisons en
dc.subject.other Query containment en
dc.subject.other Query rewriting en
dc.subject.other Query languages en
dc.title Rewriting queries using views in the presence of arithmetic comparisons en
heal.type journalArticle en
heal.identifier.primary 10.1016/j.tcs.2006.08.020 en
heal.identifier.secondary http://dx.doi.org/10.1016/j.tcs.2006.08.020 en
heal.language English en
heal.publicationDate 2006 en
heal.abstract We consider the problem of answering queries using views, where queries and views are conjunctive queries with arithmetic comparisons over dense orders. Previous work only considered limited variants of this problem, without giving a complete solution. We first show that obtaining equivalent rewritings for conjunctive queries with arithmetic comparisons is decidable. Then, we consider the problem of finding maximally contained rewritings (MCRs) where the decidability proof does not carry over. We investigate two special cases of this problem where the query uses only semi-interval comparisons. In both cases decidability of finding MCRs depends on the query containment test. First, we address the case where the homomorphism property holds in testing query containment. In this case decidability is easy to prove but developing an efficient algorithm is not trivial. We develop such an algorithm and prove that it is sound and complete. This algorithm applies in many cases where the query uses only left (or right) semi-interval comparisons. Then, we develop a new query containment test for the case where the containing query uses both left and right semi-interval comparisons but with only one left (or right) semi-interval subgoal. Based on this test, we show how to produce an MCR which is a Datalog query with arithmetic comparisons. The containment test that we develop obtains a result of independent interest. It finds another special case where query containment in the presence of arithmetic comparisons can be tested in nondeterministic polynomial time. (c) 2006 Elsevier B.V. All rights reserved. en
heal.publisher ELSEVIER SCIENCE BV en
heal.journalName Theoretical Computer Science en
dc.identifier.doi 10.1016/j.tcs.2006.08.020 en
dc.identifier.isi ISI:000242872300005 en
dc.identifier.volume 368 en
dc.identifier.issue 1-2 en
dc.identifier.spage 88 en
dc.identifier.epage 123 en

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