126 search results - page 8 / 26 » The Complexity of Acyclic Conjunctive Queries |
PODS
2009
ACM
14 years 8 months ago
2009
ACM
We consider the problem of deciding query equivalence for a conjunctive language in which queries output complex objects composed from a mixture of nested, unordered collection ty...
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...
DEXAW
2008
IEEE
13 years 9 months ago
2008
IEEE
With the increasing development of real applications using Semantic Web Technologies, it is necessary to provide scalable and efficient ontology querying and reasoning systems. In ...
VLDB
2003
ACM
14 years 7 months ago
2003
ACM
In data applications such as information integration, there can be limited access patterns to relations, i.e., binding patterns require values to be specified for certain attribut...
PODS
2003
ACM
14 years 7 months ago
2003
ACM
In this paper we study the following problem. Given a database and a set of queries, we want to find, in advance, a set of views that can compute the answers to the queries, such ...