The D2RQ API provides access to relational database content from within the Jena and Sesame RDF frameworks. D2R Server is a Semantic Web server and SPARQL endpoint based on D2RQ. Both use a declarative language for mapping database schemata to RDF.
D2RMAP is a declarative language to describe mappings between relational database schemata and OWL ontologies. This D2R processor implements the D2R mapping language and exports data from a relational database as RDF, N3, N-TRIPLES or as Jena models.