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Paper
Abstract
We consider the problem of indexing XML data for solving branching path expressions with the aim of reducing the number of joins to be executed and we propose a simple yet efficient join indexing approach to shrink the twig before applying any structural join algorithm. The indexing technique we propose, that we call XJoin Index, precomputes some structural (semi-)join results thus reducing the number of joins to be computed. Precomputed (semi-)joins support the following operations: (i) attribute selections, possibly involving several attributes; (ii) detection of parent-child relationships; (ii) counting selections, like Find all books with at least 3 authors. Unlike other approaches, based on specialized data structures XJoin Index is entirely based on B/sup +/-trees and can be coupled with any structural join algorithm proposed so far.
Authors
E. Bertino, B. Catania, Wen Qiang Wang
Journal
Proceedings. 20th International Conference on Data Engineering