121 search results - page 8 / 25 » On Containment of Conjunctive Queries with Negation |
ALT
2000
Springer
14 years 2 days ago
2000
Springer
A conjunctive query problem in relational database theory is a problem to determine whether or not a tuple belongs to the answer of a conjunctive query over a database. Here, a tup...
AMW
2009
13 years 8 months ago
2009
Abstract. Rewriting of conjunctive queries using views has many applications in database and data integration. We investigate ways to improve performance of rewriting and propose a...
ADBIS
2004
Springer
14 years 1 months ago
2004
Springer
Repairing a database means making the database consistent by applying changes that are as small as possible. Nearly all approaches to repairing have assumed deletions and insertion...
PODS
2010
ACM
14 years 24 days ago
2010
ACM
We investigate a higher-order query language that embeds operators of the positive relational algebra within the simply-typed λ-calculus. Our language allows one to succinctly de...
ACL
2003
13 years 9 months ago
2003
Standard IR systems can process queries such as “web NOT internet”, enabling users who are interested in arachnids to avoid documents about computing. The documents retrieved ...