Incrementally computing ordered answers of acyclic conjunctive queries

Benny Kimelfeld*, Yehoshua Sagiv

*Corresponding author for this work

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

20 Scopus citations

Abstract

Evaluations of SQL queries with the ORDER BY clause is considered. The naive approach of first computing the result and then sorting the tuples is not suitable for Web applications, since the result could be very large while users expect to get quickly the top-k tuples. Tractability, in this case, amounts to enumerating answers in sorted order with polynomial delay, under query-and-data complexity. It is proved that an efficient algorithm for finding the top-ranked tuple of a conjunctive query is a sufficient (and not just necessary) condition for tractability. Several classes of orders are shown to have this property when queries are acyclic.

Original languageEnglish
Title of host publicationNext Generation Information Technologies and Systems - 6th International Conference, NGITS 2006, Proceedings
PublisherSpringer Verlag
Pages141-152
Number of pages12
ISBN (Print)3540354727, 9783540354727
DOIs
StatePublished - 2006
Event6th International Conference on Next Generation Information Technologies and Systems, NGITS 2006 - Kibbutz Shefayim, Israel
Duration: 4 Jul 20066 Jul 2006

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume4032 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference6th International Conference on Next Generation Information Technologies and Systems, NGITS 2006
Country/TerritoryIsrael
CityKibbutz Shefayim
Period4/07/066/07/06

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