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ICDT
2012
ACM
251views Database» more  ICDT 2012»
12 years 2 months ago
Computing universal models under guarded TGDs
A universal model of a database D and a set Σ of integrity constraints is a database that extends D, satisfies Σ, and is most general in the sense that it contains sound and co...
André Hernich
ICDT
2012
ACM
235views Database» more  ICDT 2012»
12 years 2 months ago
Equivalence and minimization of conjunctive queries under combined semantics
The problems of query containment, equivalence, and minimization are recognized as very important in the context of query processing, specifically of query optimization. In their...
Rada Chirkova
ICDT
2012
ACM
247views Database» more  ICDT 2012»
12 years 2 months ago
A normal form for preventing redundant tuples in relational databases
We introduce a new normal form, called essential tuple normal form (ETNF), for relations in a relational database where the constraints are given by functional dependencies and jo...
Hugh Darwen, C. J. Date, Ronald Fagin
ICDT
2012
ACM
242views Database» more  ICDT 2012»
12 years 2 months ago
Win-move is coordination-free (sometimes)
In a recent paper by Hellerstein [15], a tight relationship was conjectured between the number of strata of a Datalog¬ program and the number of “coordination stages” require...
Daniel Zinn, Todd J. Green, Bertram Ludäscher
ICDT
2012
ACM
293views Database» more  ICDT 2012»
12 years 2 months ago
On the complexity of query answering over incomplete XML documents
Previous studies of incomplete XML documents have identified three main sources of incompleteness – in structural information, data values, and labeling – and addressed data ...
Amélie Gheerbrant, Leonid Libkin, Tony Tan
ICDT
2012
ACM
226views Database» more  ICDT 2012»
12 years 2 months ago
Factorised representations of query results: size bounds and readability
We introduce a representation system for relational data based on algebraic factorisation using distributivity of product over union and commutativity of product and union. We giv...
Dan Olteanu, Jakub Zavodny
ICDT
2012
ACM
226views Database» more  ICDT 2012»
12 years 2 months ago
Bounded repairability for regular tree languages
We consider the problem of repairing unranked trees (e.g., XML documents) satisfying a given restriction specification R (e.g., a DTD) into unranked trees satisfying a given targ...
Gabriele Puppis, Cristian Riveros, Slawek Staworko