121 search results - page 9 / 25 » On Containment of Conjunctive Queries with Negation |
PODS
2006
ACM
14 years 7 months ago
2006
ACM
Privacy-preserving query-answering systems answer queries while provably guaranteeing that sensitive information is kept secret. One very attractive notion of privacy is perfect p...
CIKM
2007
Springer
13 years 11 months ago
2007
Springer
How to improve search accuracy for difficult topics is an underaddressed, yet important research question. In this paper, we consider a scenario when the search results are so poo...
ICDT
2001
ACM
14 years 5 days ago
2001
ACM
In information-integration systems, source relations often have limitations on access patterns to their data; i.e., when one must provide values for certain attributes of a relatio...
PODS
1992
ACM
13 years 11 months ago
1992
ACM
: We study the problem of determining whether a given recursive Datalog program is equivalent to a given nonrecursive Datalog program. Since nonrecursive Datalog programs are equiv...
PODS
2011
ACM
12 years 10 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...