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2004
Springer

Query Answering and Containment for Regular Path Queries under Distortions

8 years 9 months ago
Query Answering and Containment for Regular Path Queries under Distortions
Abstract. We give a general framework for approximate query processing in semistructured databases. We focus on regular path queries, which are the integral part of most of the query languages for semistructured databases. To enable approximations, we allow the regular path queries to be distorted. The distortions are expressed in the system by using weighted regular expressions, which correspond to weighted regular transducers. After defining the notion of weighted approximate answers we show how to compute them in order of their proximity to the query. In the new approximate setting, query containment has to be redefined in order to take into account the quantitative proximity information in the query answers. For this, we define approximate containment, and its variants k-containment and reliable containment. Then, we give an optimal algorithm for deciding the k-containment. Regarding the reliable approximate containment, we show that it is polynomial time equivalent to the notor...
Gösta Grahne, Alex Thomo
Added 01 Jul 2010
Updated 01 Jul 2010
Type Conference
Year 2004
Where FOIKS
Authors Gösta Grahne, Alex Thomo
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