Efficient Processing SAPE Queries Using the Dynamic Labelling Structural Indexes

  • Attila Kiss
  • Vu Le Anh
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4152)


There are a variety of structural indexes which have been proposed to speed up path expression queries over XML data. They usually work by partitioning nodes in the data graph into equivalence classes and storing equivalence classes as index nodes. In most of current structural indexes, the nodes in the same partition have the same label. They are not flexible with queries containing the wild- or alternation cards, and sometimes their size is bigger than the necessity.

In this paper, we introduce the dynamic labelling structural indexes. These structural indexes only support a set of frequently used simple alternation path expressions (SAPE for short), where expressions may contain wild- or alternation cards. The labels of data nodes in the same partition may be different. The dynamic labelling not only decreases the size of the structural index, but also supports SAPE’s better. Every static labelling structural index can be improved by using dynamic labelling. Because of the limitation, in this paper we just study the DL-1-index improved from the 1-index, and the DL-A*(k)-index improved from the A(k)-index. The construction and refinement of these indexes are based on our results from the properties of partitions and the split operation. Our experiments show that the size of the improved dynamic labelling structural indexes is smaller and the query processing on these indexes is more efficient comparing to the naive ones.


Query Processing Data Graph Query Evaluation Data Node Index Node 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Attila Kiss
    • 1
  • Vu Le Anh
    • 1
  1. 1.Department of Information SystemsEötvös Loránd UniversityHungary

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