OpenLink Virtuoso

OpenLink Virtuoso

Name of the tool: OpenLink Virtuoso
Home page:
Date of latest release:
Programming language(s) that can be used with the tool: C, C++, Python, PHP, Java, Javascript, C#, ActionScript, Tcl, Perl, Ruby, Obj-C
Relevant semantic web technologies: RDF, RDFS, SPARQL, OWL, GRDDL, RDFa, RDB2RDF, R2RML, Direct Mapping
Categories: Triple Store, Reasoner, RDF Generator, SPARQL Endpoint, OWL Reasoner, RDFS Reasoner, RDB2RDF
See also:
Public mailing list:
Preferred project URI:
DOAP reference:
Company or institution: OpenLink Software

(Tool description last modified on 2012-02-11.)


OpenLink Virtuoso is a SQL-ORDBMS and Web Application Server hybrid (aka Universal Sever) that provides SQL, XML, and RDF data management in a single multithreaded server process. Triple Store access is available via SPARQL, SIMILE Semantic Bank API, ODBC, GRDDL, JDBC, ADO.NET, XMLA, WebDAV, and Virtuoso/PL (SQL Stored Procedure Language). The product is available in Open Source and Commercial editions.

Virtouso is also an OWL Reasoner. In current versions, it supports owl:sameAs, rdfs:subClassOf, and rdfs:subPropertyOf, which are sufficient for many purposes. As of 5.00.3031, owl:sameAs, owl:equivalentClass, and owl:equivalentProperty are also considered when determining subclass or subproperty relations. As of 6.10, owl:TransitiveProperty, owl:SymmetricalProperty, and owl:inverseOf have also been added. Virtuoso defaults to using backward-chaining, but if desired, forward-chaining (i.e., materialized inferences) may be forced.

Virtuoso delivers RDB2RDF (formerly known as SQL2RDF) directly; via the Sponger and its cartridges, it can also deliver RDF from GRDDL, RDFa, microformats, and many more inputs.

Virtuoso includes a Live SPARQL Query Service Endpoint in all installations. A SPARQL-to-SQL gateway for locally-housed relational data is included in both Open-Source and Commercial Editions; Commercial Edition extends SPARQL Query distribution to any ODBC- or JDBC-accessible data source, SQL-DBMS or otherwise. Additional details and usage samples (including remoting/relaying to other SPARQL Query Services) are available. Commercial edition supports SPARQL-GEO as of Release 6.1.

DBpedia, Bio2RDF, the LOD Cloud Cache, and many other large data sets on the Web are currently hosted by Virtuoso instances.

Last modified on 11 February 2012, at 08:13