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Query reformulation with constraints

Tue, 03/13/2007 - 10:02 — huliganka
Authors: 
Deutsch, A.; Popa, L.; Tannen, V.
Author: 
Deutsch, A
Popa, L
Tannen, V
Year: 
2006
Venue: 
SIGMOD 2006
URL: 
http://portal.acm.org/citation.cfm?id=1122010&dl=acm&coll=&CFID=15151515&CFTOKEN=6184618
DOI: 
http://doi.acm.org/10.1145/1121995.1122010
Citations: 
0
Citations range: 
n/a
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Deutsch2006Queryreformulationwith.pdf356.58 KB

Let Σ1, Σ2 be two schemas, which may overlap, C be a set of constraints on the joint schema Σ1 ∪ Σ2, and q1 be a Σ1-query. An (equivalent) reformulation of q1 in the presence of C is a Σ2-query, q2, such that q2 gives the same answers as q1 on any Σ1 ∪ Σ2-database instance that satisfies C. In general, there may exist multiple such reformulations and choosing among them may require, for example, a cost model.