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dc.contributor.authorΓεργατσούλης, Μανώληςel_GR
dc.contributor.authorΑφράτη, Φώτοel_GR
dc.contributor.authorDamigos, M.en
dc.contributor.authorGergatsoulis, Manolisen
dc.contributor.authorAfrati, Fotoen
dc.date.available2014-01-13T11:24:51Z
dc.date.issued2010
dc.identifier.issn200190
dc.identifier.urihttp://hdl.handle.net/10797/13665en
dc.descriptionΠεριέχει το πλήρες κείμενοel_GR
dc.description.abstractConjunctive queries (CQs) are at the core of query languages encountered in many logic-based research fields such as AI, or database systems. The majority of existing work assumes set semantics but often in real applications the manipulation of duplicate tuples is required. One of the major problems that arises as part of advanced features of query optimization, data integration, query reformulation and many other research topics is testing for containment of such queries. In this work, we investigate the complexity of query containment problem for CQs under bag semantics (i.e. duplicate tuples are allowed in both the database and the results of queries) and under bag-set semantics (i.e. duplicates are allowed in the result of the queries but not in the database). We derive complexity results for these problems for five major subclasses of CQs; and we also find necessary conditions for CQ query containment. The general case of these problems remains open.en
dc.language.isoengen
dc.rightsinfo:eu-repo/semantics/openAccessen
dc.sourceInformation Processing Letters Volume 110, Issue 10, 30 April 2010, Pages 360-369en
dc.sourceScopusen
dc.source.urihttp://www.scopus.com/record/display.url?eid=2-s2.0-77949916906&origin=resultslist&sort=plf-f&src=s&st1=gergatsoulis&st2=&nlo=1&nlr=20&nls=count-f&sid=D9369EFF27F81ECA48474BAE855DB2E1.WlW7NKKC52nnQNxjqAQrlA%3a63&sot=anl&sdt=aut&sl=41&s=AU-ID%28%22Gergatsoulis%2c+Manolis%22+6602969138%29&relpos=10&relpos=10&citeCnt=5&searchTerm=AU-ID%28%5C%26quot%3BGergatsoulis%2C+Manolis%5C%26quot%3B+6602969138%29en
dc.titleQuery containment under bag and bag-set semanticsen
dc.typeArticleen
dc.subject.uncontrolledtermDatabaseen
dc.subject.uncontrolledtermBag semanticsen
dc.subject.uncontrolledtermBag-set semanticsen
dc.subject.uncontrolledtermConjunctive queriesen
dc.subject.uncontrolledtermQuery containmenten
dc.subject.JITAΠηγές πληροφορησης, υποστήριξη, δίαυλοι, Βάσεις δεδομένων και δικτύωση βάσεων δεδομένωνel_GR
dc.subject.JITAInformation sources, supports, channels, Databases and DataBase Networkingen
dc.identifier.JITAHLen


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