31 search results - page 1 / 7 » Some Algorithmic Improvements for the Containment Problem of... |
ICDT
2007
ACM
13 years 10 months ago
2007
ACM
Query containment is a fundamental problem of databases. Given two queries q1 and q2, it asks whether the set of answers to q1 is included in the set of answers to q2 for any datab...
ADBIS
2009
Springer
13 years 11 months ago
2009
Springer
Abstract. We consider the problem of query containment for conjunctive queries with the safe negation property. Some necessary conditions for this problem are given. A part of the ...
DEXA
2010
Springer
13 years 4 months ago
2010
Springer
We consider the containment problem for conjunctive queries with atomic negation. Firstly, we refine an existing algorithm based on homomorphism checks, which itself improves other...
EDBT
2004
ACM
14 years 4 months ago
2004
ACM
We study the problem of answering queries over sources with limited access patterns. The problem is to decide whether a given query Q is feasible, i.e., equivalent to an executable...
PODS
2011
ACM
12 years 7 months ago
2011
ACM
In deletion propagation, tuples from the database are deleted in order to reflect the deletion of a tuple from the view. Such an operation may result in the (often necessary) del...