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Query Processing and Optimization for Regular Path Expressions

  • Guoren Wang
  • Mengchi Liu
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2681)

Abstract

Regular path expression is one of the core components of XML query languages, and several approaches to evaluating regular path expressions have been proposed. In this paper, a new path expression evaluation approach, extent join, is proposed to compute both parent-children (‘/’) and ancestor-descendent (‘//’) connectors between path steps. Furthermore, two path expression optimization rules, path-shortening and path-complementing, are proposed. The former reduces the number of joins by shortening the path while the latter optimizes the execution of a path by using an equivalent complementary path expression to compute the original path. Experimental results show that the algorithms proposed in this paper are much more efficient than conventional ones.

Keywords

Query Processing Query Optimization Query Plan Path Query Path Expression 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Zhou, A., Lu, H., Zheng, S., Liang, Y., Zhang, L., Ji, W., Tian, Z.: VXMLR: A Visual XML-Relational Database System. In: Proceedings of the 27th VLDB Conference. Morgan Kaufmann. Roma, Italy (2001) 719–720Google Scholar
  2. 2.
    Li, Q., Moon, B.: Indexing and querying XML Data for regular path expressions. In: Proceedings of the 27th VLDB Conference. Morgan Kaufmann. Roma, Italy (2001) 361–370Google Scholar
  3. 3.
    Chamberlin, D., Robie, J., Florescu, D.: Quilt: An XML Query Language for Heterogeneous Data Sources. In: Proceedings of 3rd International Workshop WebDB. Lecture Notes in Computer Science Vol 1997. Dallas (2000) 1–25Google Scholar
  4. 4.
    Fankhauser, P.: XQuery Formal Semantics: State and Challenges. SIGMOD Record. 3 (2001) 14–19CrossRefGoogle Scholar
  5. 5.
    Robie, J., Lapp, J., Schach, D.: XML Query Language (XQL). http://www.w3.org/TandS/QL/QL98/cfp (1998)
  6. 6.
    Cark, J., DeRose, S.: XMP Path Language (XPath). Technical Report REC-xpath-19991116, W3C (1999)Google Scholar
  7. 7.
    Abiteboul, S., Quass, D., McHugh, J., Widom, J., Wiener, J.: The Lorel Query Language for Semistructured Data. Int’l J. Digital Libraries. 1 (1997) 68–88Google Scholar
  8. 8.
    Lu, H., Wang, G., Yu, G., Bao, Y., Lv, J., Yu, Y.: Xbase: Making your gigabyte disk queriable. In Proceedings of the 2002 ACM SIGMOD Conference. ACM Press. Madison, Wisconsin (2002) 630–630CrossRefGoogle Scholar
  9. 9.
    Cattel, R.G.G, Barry, D., Berler, M., et al.: The object data standard: ODMG 3.0. Morgan Kaufmann (2000)Google Scholar
  10. 10.
    Rahm, E., Bohme, T.: XMach-1: A Multi-User Benchmark for XML Data Management, In: Proceedings of 1st VLDB Workshop on Efficiency and Effectiveness of XML Tools, and Techniques. Lecture Notes in Computer Science Vol 2590. Springer-Verlag, Berlin Heidelberg. Hong Kong, China (2002) 35–46Google Scholar
  11. 11.
    Schmidt, A., Waas, M., Kersten, M.L., Carey, M.J., Manolescu, I., Busse, R.: XMark: A Benchmark for XML Data Management. In: Proceedings of 28th VLDB Conference. Morgan Kaufmann. Hong Kong, China (2002) 974–985Google Scholar
  12. 12.
    Jiang, H., Lu, H., Wang, W., Yu, J.X.: Path Materialization Revisited: An Efficient Storage Model for XML Data. In: Proceedings of Thirteenth Australasian Database Conference. Australian Computer Society Inc. Melbourne, Victoria (2002)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  • Guoren Wang
    • 1
  • Mengchi Liu
    • 1
  1. 1.School of Computer ScienceCarleton UniversityOttawaCanada

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