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Summary: Query Optimization for Structured Documents Based on Knowledge
on the Document Type De nition
Klemens Bohm Karl Aberer
Institute of Inf. Systems GMD{IPSI
ETH Zentrum Dolivostr. 15
8092 Zurich, Switzerland 64293 Darmstadt, Germany
M. Tamer Ozsu Kathrin Gayer
Dept. of Computing Science Dept. of Economics and Computing Science
University of Alberta Humboldt University Berlin
Edmonton, Alberta, Canada T6G 2H1 10178 Berlin, Germany
Abstract
Declarative access mechanisms for structured
document collections and for semi-structured data
are becoming increasingly important. In this article,
using a rule-based approach for query optimization
and applying it to such queries, we deploy knowledge
on the Document Type De nition (DTD) to formulate
transformation rules for query-algebra terms. Speci -
cally, we look at rules that save navigation along paths
by cutting o these paths or by replacing them with
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