59 search results - page 1 / 12 » Containment of conjunctive queries on annotated relations |
ICDT
2009
ACM
14 years 5 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...
DLOG
1997
13 years 6 months ago
1997
ERSHOV
2009
Springer
13 years 11 months 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...
GEOINFORMATICA
2011
12 years 11 months ago
2011
Discovery of suitable web services is a crucial task in Spatial Data Infrastructures (SDI). In this work, we develop a novel approach to the discovery of geoprocessing services (WP...
ICDT
2007
ACM
13 years 11 months ago
2007
ACM
Abstract. We study containment of conjunctive queries that are evaluated over databases that may contain tuples with null values. We assume the semantics of SQL for single block qu...