D2RQ - Treating Non-RDF Databases as Virtual RDF Graphs - Chris Bizer As Semantic Web technologies are getting mature, there is a growing need for RDF applications to access the content of non-RDF, legacy databases without having to replicate the whole database into RDF. D2RQ is a declarative language to describe mappings between relational database schemata and OWL/RDFS ontologies. The mappings allow RDF applications to access the content of huge, non-RDF databases using Semantic Web query languages like SPARQL.
2007-06-23