383 search results - page 2 / 77 » Query Containment for Conjunctive Queries with Regular Expre... |
ICDT
2009
ACM
14 years 6 months ago
2009
ACM
We study containment and equivalence of (unions of) conjunctive queries on relations annotated with elements of a commutative semiring. Such relations and the semantics of positiv...
FOIKS
2004
Springer
13 years 10 months ago
2004
Springer
Abstract. We give a general framework for approximate query processing in semistructured databases. We focus on regular path queries, which are the integral part of most of the que...
PODS
2003
ACM
14 years 5 months ago
2003
ACM
In this paper we consider general path constraints for semistructured databases. Our general constraints do not suffer from the limitations of the path constraints previously stud...
PVLDB
2010
13 years 3 months ago
2010
Virtual views are a mechanism that facilitates re-use and makes queries easier to express. However the use of iterative view definitions makes very simple query evaluation and an...
ERSHOV
2009
Springer
14 years 11 hour ago
2009
Springer
Abstract. We consider the problem of query containment for conjunctive queries with safe negation property. A necessary and sufficient condition for two queries to be in containmen...