New Rewritings and Optimizations for Regular Path Queries

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New Rewritings and Optimizations for Regular Path Queries
All the languages for querying semistructured data and the web use as an integral part regular expressions. Based on practical observations, finding the paths that satisfy those regular expressions is very expensive. In this paper, we introduce the “maximal partial rewritings” (MPR’s) for regular path queries using views. The MPR’s are always exact and more useful for the optimization of the regular path queries than other rewritings from previously known methods. We develop an algorithm for computing MPR’s and prove, through a complexity theoretic analysis, that our algorithm is essentially optimal. Also, we present query answering algorithms that utilize exact partial rewritings for regular path queries and conjunctive regular path queries respectively.
Gösta Grahne, Alex Thomo
Added 06 Jul 2010
Updated 06 Jul 2010
Type Conference
Year 2003
Where ICDT
Authors Gösta Grahne, Alex Thomo
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