Matching twigs in probabilistic XML

Benny Kimelfeld, Yehoshua Sagiv

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

71 Scopus citations

Abstract

Evaluation of twig queries over probabilistic XML is investigated. Projection is allowed and, in particular, a query may be Boolean. It is shown that for a well-known model of probabilistic XML, the evaluation of twigs with projection is tractable under data complexity (whereas in other probabilistic data models, projection is intractable). Under query-and-data complexity, the problem becomes intractable even without projection (and for rather simple twigs and data). In earlier work on probabilistic XML, answers are always complete. However, there is often a need to produce partial answers because XML data may have missing sub-elements and, furthermore, complete answers may be deemed irrelevant if their probabilities are too low. It is shown how to define a semantics that provides partial answers that are maximal with respect to a probability threshold, which is specified by the user. For this semantics, it is shown how to efficiently evaluate twigs, even under query-and-data complexity if there is no projection.

Original languageEnglish
Title of host publication33rd International Conference on Very Large Data Bases, VLDB 2007 - Conference Proceedings
EditorsJohannes Gehrke, Christoph Koch, Minos Garofalakis, Karl Aberer, Carl-Christian Kanne, Erich J. Neuhold, Venkatesh Ganti, Wolfgang Klas, Chee-Yong Chan, Divesh Srivastava, Dana Florescu, Anand Deshpande
PublisherAssociation for Computing Machinery, Inc
Pages27-38
Number of pages12
ISBN (Electronic)9781595936493
StatePublished - 2007
Event33rd International Conference on Very Large Data Bases, VLDB 2007 - Vienna, Austria
Duration: 23 Sep 200727 Sep 2007

Publication series

Name33rd International Conference on Very Large Data Bases, VLDB 2007 - Conference Proceedings

Conference

Conference33rd International Conference on Very Large Data Bases, VLDB 2007
Country/TerritoryAustria
CityVienna
Period23/09/0727/09/07

Bibliographical note

Publisher Copyright:
Copyright 2007 VLDB Endowment, ACM.

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