285 search results - page 4 / 57 » Optimization of Real Conjunctive Queries |
DLOG
2006
13 years 8 months ago
2006
The novel context of accessing and querying large data repositories through ontologies that are formalized in terms of expressive DLs requires on the one hand to consider query an...
VLDB
2005
ACM
14 years 5 days ago
2005
ACM
Cost-based query optimizers need to estimate the selectivity of conjunctive predicates when comparing alternative query execution plans. To this end, advanced optimizers use multi...
DLOG
2007
13 years 9 months ago
2007
We present cq-programs, which enhance nonmonotonic description logics (dl-) programs by conjunctive queries (CQ) and union of conjunctive queries (UCQ) over Description Logics kno...
ER
2008
Springer
13 years 8 months ago
2008
Springer
Access limitations may occur when querying data sources over the web or heterogeneous data sources presented as relational tables: this happens, for instance, in Data Exchange and ...
AAAI
2006
13 years 8 months ago
2006
Description Logics (DLs) are the formal foundations of the standard web ontology languages OWL-DL and OWL-Lite. In the Semantic Web and other domains, ontologies are increasingly ...