Heuristic containment check of partial tree-pattern queries in the presence of index graphs

Dimitri Theodoratos, Stefanos Souldatos, Theodore Dalamagas, Pawel Placek, Timos Sellis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

The wide adoption of XML has increased the interest of the database community on tree-structured data management techniques. Querying capabilities are provided through tree-pattern queries. The need for querying tree-structured data sources when their structure is not fully known, and the need to integrate multiple data sources with different tree structures have driven, recently, the suggestion of query languages that relax the complete specification of a tree pattern. In this paper, we use a query language which allows partial tree-pattern queries (PTPQs). The structure in a PTPQ can be flexibly specified fully, partially or not at all. To evaluate a PTPQ, we exploit index graphs which generate an equivalent set of "complete" tree-pattern queries.In order to process PTPQs, we need to efficiently solve the PTPQ satisfiability and containment problems. These problems become more complex in the context of PTPQs because the partial specification of the structure allows new, non-trivial, structural expressions to be derived from those explicitly specified in a PTPQ. We address the problem of PTPQ satisfiability and containment in the absence and in the presence of index graphs, and we provide necessary and sufficient conditions for each case. To cope with the high complexity of PTPQ containment in the presence of index graphs,we study a family of heuristic approaches for PTPQ containment based on structural information extracted from the index graph in advance and on-the-fly. We implement our approaches and we report on their extensive experimental evaluation and comparison.

Original languageEnglish (US)
Title of host publicationProceedings of the 15th ACM Conference on Information and Knowledge Management, CIKM 2006
Pages445-454
Number of pages10
DOIs
StatePublished - Dec 1 2006
Event15th ACM Conference on Information and Knowledge Management, CIKM 2006 - Arlington, VA, United States
Duration: Nov 6 2006Nov 11 2006

Publication series

NameInternational Conference on Information and Knowledge Management, Proceedings

Other

Other15th ACM Conference on Information and Knowledge Management, CIKM 2006
CountryUnited States
CityArlington, VA
Period11/6/0611/11/06

All Science Journal Classification (ASJC) codes

  • Decision Sciences(all)
  • Business, Management and Accounting(all)

Keywords

  • Partial tree-pattern query
  • Query containment
  • Tree-structured data

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