39 search results - page 7 / 8 » Data Complexity of Answering Unions of Conjunctive Queries i... |
PODS
2010
ACM
13 years 11 months ago
2010
ACM
Both semantic and type-based query optimization rely on the idea that queries often exhibit non-trivial rewritings if the state space of the database is restricted. Despite their ...
PVLDB
2010
13 years 4 months ago
2010
Ontology-based data access is a powerful form of extending database technology, where a classical extensional database (EDB) is enhanced by an ontology that generates new intensio...
ICDT
2003
ACM
13 years 11 months ago
2003
ACM
All the languages for querying semistructured data and the web use as an integral part regular expressions. Based on practical observations, finding the paths that satisfy those r...
AMW
2009
13 years 7 months ago
2009
In data exchange, data are materialised from a source schema to a target schema, according to suitable source-to-target constraints. Constraints are also expressed on the target sc...
SEMWEB
2009
Springer
14 years 23 days ago
2009
Springer
An important issue for the Semantic Web is how to combine open-world ontology languages with closed-world (non-monotonic) rule paradigms. Several proposals for hybrid languages all...