On the Query Evaluation in Document DBs

  • Yangjun Chen
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4080)


In this paper, we study the query evaluation in document databases. First, we show that a query represented in an XML language can be generally considered as a la beled tree, and the evaluation of such a query is in fact a tree embedding problem. Then, we propose a strategy to solve this problem, based on dynamic programming. For the ordered tree embedding, the proposed algorithm needs only O(|T|(|P|) time and O(|T|(|P|) space, where |T| and |P| stands for the numbers of the nodes in the target tree T and the pattern tree P, respectively. This computational complexity is better than any existing method on this issue. In addition, how to adapt this method to the general tree embedding is also discussed.


Parse Tree Virtual Node Query Evaluation Conjunctive Query Label Tree 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Yangjun Chen
    • 1
  1. 1.Department of Applied Computer ScienceUniversity of WinnipegWinnipegCanada

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