View source for OpenLink Virtuoso

{{Tool
 | Name=OpenLink Virtuoso
 | Homepage=virtuoso.openlinksw.com/
 | ProgrammingLanguage1=C
 | ProgrammingLanguage2=C++
 | ProgrammingLanguage3=Python
 | ProgrammingLanguage4=PHP
 | ProgrammingLanguage5=Java
 | ProgrammingLanguage6=Javascript
 | ProgrammingLanguage7=C#
 | ProgrammingLanguage8=ActionScript
 | ProgrammingLanguage9=Tcl
 | ProgrammingLanguage10=Perl
 | ProgrammingLanguage11=Ruby
 | ProgrammingLanguage12=Obj-C
 | SWTechnology1=RDF
 | SWTechnology2=RDFS
 | SWTechnology3=SPARQL
 | SWTechnology4=OWL
 | SWTechnology5=GRDDL
 | SWTechnology6=RDFa
 | SWTechnology7=RDB2RDF
 | SWTechnology8=R2RML
 | SWTechnology9=Direct Mapping
 | Category1=Triple Store
 | Category2=Reasoner
 | Category3=RDF Generator
 | Category4=SPARQL Endpoint
 | Category5=OWL Reasoner
 | Category6=RDFS Reasoner
 | Category7=RDB2RDF
 | SeeAlso=esw.w3.org/topic/VirtuosoUniversalServer
 | Institution=OpenLink Software
 | PublicMailingList=lists.sourceforge.net/lists/listinfo/virtuoso-users
 | DOAPFile=www.openlinksw.com/DOAP/doap_VOS.rdf
}}


''[http://virtuoso.openlinksw.com/ OpenLink Virtuoso]'' is a [http://virtuoso.openlinksw.com/wiki/main/Main/VOSRDFWP 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 [http://virtuoso.openlinksw.com/wiki/main/ Open Source] and [http://download.openlinksw.com/ Commercial] editions.

Virtouso is also an [[OWL]] Reasoner.  [http://docs.openlinksw.com/virtuoso/rdfsparqlrule.html In current versions], it supports <tt>owl:sameAs</tt>, <tt>rdfs:subClassOf</tt>, and <tt>rdfs:subPropertyOf</tt>, which are sufficient for many purposes.  As of 5.00.3031, <tt>owl:sameAs</tt>, <tt>owl:equivalentClass</tt>, and <tt>owl:equivalentProperty</tt> are also considered when determining subclass or subproperty relations.  As of 6.10, <tt>owl:TransitiveProperty</tt>, <tt>owl:SymmetricalProperty</tt>, and <tt>owl:inverseOf</tt> 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 [http://docs.openlinksw.com/virtuoso/virtuososponger.html Sponger and its cartridges], it can also deliver [[RDF]] from [[GRDDL]], [[RDFa]], [[microformats]], and many more inputs.

Virtuoso includes a [http://demo.openlinksw.com/sparql/ 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) [http://demo.openlinksw.com/sparql_demo 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.

* Main product site: http://virtuoso.openlinksw.com/
* Open Source Project page: http://virtuoso.openlinksw.com/wiki/main/