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ICDT
2007
ACM
126views Database» more  ICDT 2007»
13 years 9 months ago
Containment of Conjunctive Queries over Databases with Null Values
Abstract. We study containment of conjunctive queries that are evaluated over databases that may contain tuples with null values. We assume the semantics of SQL for single block qu...
Carles Farré, Werner Nutt, Ernest Teniente,...
EDBTW
2006
Springer
13 years 7 months ago
Semantically Correct Query Answers in the Presence of Null Values
For several reasons a database may not satisfy a given set of integrity constraints (ICs), but most likely most of the information in it is still consistent with those ICs; and cou...
Loreto Bravo, Leopoldo E. Bertossi
DBPL
2007
Springer
119views Database» more  DBPL 2007»
13 years 9 months ago
Conjunctive Query Containment over Trees
Abstract. The complexity of containment and satisfiability of conjunctive queries over finite, unranked, labeled trees is studied with respect to the axes Child, NextSibling, the...
Henrik Björklund, Wim Martens, Thomas Schwent...
PODS
2006
ACM
196views Database» more  PODS 2006»
14 years 3 months ago
The containment problem for REAL conjunctive queries with inequalities
Query containment is a fundamental algorithmic problem in database query processing and optimization. Under set semantics, the query-containment problem for conjunctive queries ha...
T. S. Jayram, Phokion G. Kolaitis, Erik Vee