Virtuoso is an innovative industry standards compliant platform for native data, information, and knowledge management. It implements and supports a broad spectrum of query languages, data access interfaces, protocols, and data representation formats that includes: SQL, SPARQL, ODBC, JDBC, HTTP, WebDAV, XML, RDF, RDFa, and many more.
In addition to its core data management capabilities, Virtuoso also delivers sophisticated Data Virtualization functionality enabling the construction of federated views -- which may or may not be materialized -- over heterogeneous RDBMS, Web Services, and Hypermedia data sources.
The open-source edition of Virtuoso, which includes a scalable high-performance RDF Quad Store, will be the basis for the LOD2 Stack's knowledge store.