By Topic

Efficient computation of aggregate structural joins

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Kaiyang Liu ; Dept. of Comput. Sci., Univ. of Sci. & Technol., Hong Kong, China ; Lochovsky, F.H.

Although several XML query-processing techniques have been proposed to do structural joins, no work has been done to handle aggregate structural join, which computes the aggregate value for two given XML element sets. One important kind of aggregate structural join is to determine the exact selectivity of a structural join, which proves to be crucial for overall path expression optimization and on-line systems. Related work has been done to estimate the selectivity of a path expression by applying summary techniques for XML data based on either tree simplification or a Markov model. However, because of either space restrictions or performance issues (for example, previous approaches may need to store the whole XML tree to answer an aggregate structural join), they are not applicable for aggregate structural joins. In this paper, we consider a modified aggregate B-tree, which we call a XA-tree, to index the aggregate attribute values of XML elements. Since it is based on the B-tree, the XA-tree supports query and update efficiently and places little additional burden on database administrators. Two basic algorithms are proposed to compute aggregate structural joins efficiently by utilizing the XA-tree. Furthermore, a heuristic is also proposed to further improve the performance significantly. Extensive experiments have confirmed that our approaches greatly outperform competitors by an order of magnitude.

Published in:

Web Information Systems Engineering, 2003. WISE 2003. Proceedings of the Fourth International Conference on

Date of Conference:

10-12 Dec. 2003