Optimization of a subclass of conjunctive queries

Pratul Dublish, Joachim Biskup, Yehoshua Sagiv

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

The optimization problem for a subclass of conjunctive queries which is formed by the union of the class of fan-out free queries and a subclass of typed fan-out queries is investigated. The typed fan-out queries in this class are obtained from simple tableaux by allowing at most one attribute to violate the simple-tableau property. The optimization problem for several restricted subsets of typed fan-out queries is already known to be NP-hard. It is shown that the queries under consideration possess several useful properties which are then used to obtain an O(n2) optimization algorithm based on the implication graph technique. The optimization of typed fan-out queries, obtained from simple tableaux by allowing at most two attributes to violate the simple tableau property, is shown to be NP-hard.

Original languageEnglish
Title of host publicationICDT 1990 - 3rd International Conference on Database Theory, Proceedings
EditorsSerge Abiteboul, Paris C. Kanetlakis
PublisherSpringer Verlag
Pages453-469
Number of pages17
ISBN (Print)9783540535072
DOIs
StatePublished - 1990
Event3rd International Conference on Database Theory, ICDT 1990 - Paris, France
Duration: 12 Dec 199014 Dec 1990

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume470 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference3rd International Conference on Database Theory, ICDT 1990
Country/TerritoryFrance
CityParis
Period12/12/9014/12/90

Bibliographical note

Publisher Copyright:
© Springer-Verlag Berlin Heidelberg 1990.

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