204 search results - page 10 / 41 » Containment of Conjunctive Queries with Negation: Algorithms... |
WWW
2011
ACM
13 years 2 months ago
2011
ACM
The problem of answering SPARQL queries over virtual SPARQL views is commonly encountered in a number of settings, including while enforcing security policies to access RDF data, ...
WIDM
2003
ACM
14 years 29 days ago
2003
ACM
Query rewriting using views is an essential issue in data integration. A number of algorithms, e.g., the bucket algorithm, the inverse rules algorithm, the SVB algorithm and the M...
DEXAW
1998
IEEE
13 years 12 months ago
1998
IEEE
Materialized views offer opportunities for significant performance gain in query evaluation by providing fast access to pre-computed data. The question of when and how to use a ma...
SEMWEB
2009
Springer
14 years 2 months ago
2009
Springer
An important application of semantic web technology is recognizing human-defined concepts in text. Query transformation is a strategy often used in search engines to derive querie...
ICDT
2005
ACM
14 years 1 months ago
2005
ACM
We study the problem of rewriting queries using views in the presence of access patterns, integrity constraints, disjunction, and negation. We provide asymptotically optimal algori...