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Erschienen in:
2005 | OriginalPaper | Buchkapitel
Containment of Conjunctive Queries with Arithmetic Expressions
verfasst von : Ali Kiani, Nematollaah Shiri
Erschienen in: On the Move to Meaningful Internet Systems 2005: CoopIS, DOA, and ODBASE
Verlag: Springer Berlin Heidelberg
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We study the problem of query containment for conjunctive queries with arithmetic constraints (QWAE). Such queries arise naturally in conventional database applications, information integration, and cooperative information systems. Given two such queries
Q
1
and
Q
2
, we propose an algorithm that decides the containment
$Q_2\sqsubseteq Q_1$
. The proposed algorithm returns a QWAE
Q
2
′ obtained by rewriting
Q
2
′ such that
$Q_2'\sqsubseteq Q_2$
. This provides partial answers to the QWAE
Q
1
, which would otherwise be discarded by existing standard or extended techniques for query containment.