X2QL: An eXtensible XML Query Language Supporting User-Defined Foreign Functions

  • Norihide Shinagawa
  • Hiroyuki Kitagawa
  • Yoshiharu Ishikawa
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1884)


With the recent and rapid advance of the Internet, management of structured documents such as XML documents and their databases has become more and more important. A number of query languages for XML documents have been proposed up to the present. Some of them enable tag-based powerful document structure manipulation. However, their contents processing capability is very limited. Here, the contents processing implies the similarity-based selection, ranking, summary generation, topic extraction, and so on, as well as simple string-based pattern matching. In this paper, we propose an extensible XML query language X2QL, which features inclusion of user-defined foreign functions to process document contents in the context of XML-QL-based document structure manipulation. This feature makes it possible to integrate application-oriented high-level contents processing facilities into querying documents. We also describe an implementation of an X QL query processing systemon top of XSLT processors.


Query Language Location Path Skolem Function Context Node Topic Extraction 
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.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Norihide Shinagawa
    • 1
  • Hiroyuki Kitagawa
    • 2
  • Yoshiharu Ishikawa
    • 2
  1. 1.Doctoral Program in EngineeringUniversity of TsukubaJapan
  2. 2.Institute of Information Sciences and ElectronicsUniversity of TsukubaIbarakiJapan

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