Structural Properties of XPath Fragments

  • Michael Benedikt
  • Wenfei Fan
  • Gabriel M. Kuper
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2572)

Abstract

We study structural properties of each of the main sublanguages of XPath [8] commonly used in practice. First, we characterize the expressive power of these language fragments in terms of both logics and tree patterns. Second, we investigate closure properties, focusing on the ability to perform basic Boolean operations while remaining within the fragment. We give a complete picture of the closure properties of these fragments, treating XPath expressions both as functions of arbitrary nodes in a document tree, and as functions that are applied only at the root of the tree. Finally, we provide sound and complete axiom systems and normal forms for several of these fragments. These results are useful for simplification of XPath expressions and optimization of XML queries.

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References

  1. 1.
    S. Amer-Yahia, S. Cho, V. Lakshmaman, and D. Srivistava. Minimization of tree pattern queries. In SIGMOD, 2001.Google Scholar
  2. 2.
    A. Berglund et al. XML Path Language (XPath) 2.0. W3C Working Draft, Dec. 2001. http://www.w3.org/TR/xpath20.
  3. 3.
    G. Bex, S. Maneth, and F. Neven. A formal model for an expressive fragment of XSLT. Information Systems, 27(1):21–39, 2002.MATHCrossRefGoogle Scholar
  4. 4.
    D. Calvanese, G. De Giacomo, M. Lenzerini, and D. Nardi. Reasoning in expressive description logics. In Handbook of Automated Reasoning, pages 1581–1634. Elsevier, 2001.Google Scholar
  5. 5.
    D. Chamberlin et al. XQuery 1.0: An XML query language. W3C Working Draft, June 2001. http://www.w3.org/TR/xquery.
  6. 6.
    C. Chan, P. Felber, M. Garofalakis, and R. Rastogu. Efficient filtering of XML documents with XPath expressions. In ICDE, 2002.Google Scholar
  7. 7.
    J. Clark. XSL Transformations (XSLT). W3C Recommendation, Nov. 1999. http://www.w3.org/TR/xslt.
  8. 8.
    J. Clark and S. DeRose. XML Path Language (XPath). W3C Recommendation, Nov. 1999. http://www.w3.org/TR/xpath.
  9. 9.
    A. Deutsch and V. Tannen. Containment for classes of XPath expressions under integrity constraints. In KRDB, 2001.Google Scholar
  10. 10.
    G. Gottlob, C. Koch, and R. Pichler. Efficient algorithms for processing XPath queries. In VLDB, 2002.Google Scholar
  11. 11.
    D. Harel, D. Kozen, and J. Tiuryn. Dynamic Logic. The MIT Press, 2000.Google Scholar
  12. 12.
    C. Hoffmann and M. O’Donnell. Pattern matching in trees. JACM, 29(1):68–95, 1982.MATHCrossRefMathSciNetGoogle Scholar
  13. 13.
    P. Kilpelainen and H. Manilla. Ordered and unordered tree inclusion. SIAM J. Comput., 24(2):340–356, 1995.CrossRefMathSciNetGoogle Scholar
  14. 14.
    G. Miklau and D. Suciu. Containment and equivalence of XPath expressions. In PODS, 2002.Google Scholar
  15. 15.
    T. Milo, D. Suciu, and V. Vianu. Typechecking for XML transformers. In PODS, 2001.Google Scholar
  16. 16.
    M. Murata. Extended path expressions for XML. In PODS, 2001.Google Scholar
  17. 17.
    F. Neven and T. Schwentick. Expressive and efficient languages for tree-structured data. In PODS, 2000.Google Scholar
  18. 18.
    D. Olteanu, H. Meuss, T. Furche, and F. Bry. XPath: Looking forward. In Workshop on XML-Based Data Management (XMLDM), 2002.Google Scholar
  19. 19.
    P. Ramanan. Efficient algorithms for minimizing tree pattern queries. In SIGMOD, 2002.Google Scholar
  20. 20.
    V. Redko. On defining relations for the algebra of regular events. Ukrainskii Matematicheskii Zhurnal, 16:120–126, 1964. (Russian).MathSciNetGoogle Scholar
  21. 21.
    J. Robie, J. Lapp, and D. Schach. XML Query Language (XQL). Workshop on XML Query Languages, Dec. 1998.Google Scholar
  22. 22.
    H. Thompson et al. XML Schema. W3C Working Draft, May 2001. http://www.w3.org/XML/Schema.
  23. 23.
    P. Wadler. Two semantics for XPath. Technical report, Bell Labs, 2000.Google Scholar
  24. 24.
    P. Wood. On the equivalence of XML patterns. In Computational Logic, 2000.Google Scholar
  25. 25.
    P. Wood. Minimising simple XPath expressions. In WebDB, 2001.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  • Michael Benedikt
    • 1
  • Wenfei Fan
    • 1
  • Gabriel M. Kuper
    • 2
  1. 1.Bell LaboratoriesMurray HillUSA
  2. 2.Università di TrentoTrentoItaly

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