http://docs.openlinksw.com/virtuoso/rdfandsparql.html RDF Data Access and Data Management OpenLink Virtuoso Universal Server: Documentation virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com 2009-11-16T14:26:59Z OpenLink Software Documentation Team http://docs.openlinksw.com/virtuoso/../images/misc/logo.jpg http://docs.openlinksw.com/virtuoso/rdfdatarepresentation.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com Data Representation 2009-11-16T14:26:59Z Data Representation This section covers how Virtuoso stores RDF triples. The IRI_ID built-in data type is introduced, along with the default table structures used for triple persistency. These details are mostly hidden from users of RDF, thus this section is not necessary reading for typical use of Virtuoso with RDF. http://docs.openlinksw.com/virtuoso/rdfsparql.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com SPARQL 2009-11-16T14:26:59Z SPARQL http://docs.openlinksw.com/virtuoso/rdfgraphsecurity.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com RDF Graphs Security 2009-11-16T14:26:59Z RDF Graphs Security http://docs.openlinksw.com/virtuoso/rdfrdfviewgnr.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com Automated Generation of RDF Views over Relational Data Sources 2009-11-16T14:26:59Z Automated Generation of RDF Views over Relational Data Sources http://docs.openlinksw.com/virtuoso/rdfinsertmethods.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com RDF Insert Methods in Virtuoso 2009-11-16T14:26:59Z RDF Insert Methods in Virtuoso http://docs.openlinksw.com/virtuoso/rdfsparqlintegrationmiddleware.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com Integration Middleware 2009-11-16T14:26:59Z Integration Middleware http://docs.openlinksw.com/virtuoso/rdfiridereferencing.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com Linked Data 2009-11-16T14:26:59Z Linked Data There are many cases when RDF data should be retrieved from remote sources only when really needed. E.g., a scheduling application may read personal calendars from personal sites of its users. Calendar data expire quickly, so there's no reason to frequently re-load them in hope that they are queried before expired. Virtuoso extends SPARQL so it is possible to download RDF resource from a given IRI, parse them and store the resulting triples in a graph, all three operations will be performed during the SPARQL query execution. The IRI of graph to store triples is usually equal to the IRI where the resource is download from, so the feature is named "IRI dereferencing" There are two different use cases for this feature. In simple case, a SPARQL query contains from clauses that enumerate graphs to process, but there are no triples in DB.DBA.RDF_QUAD that correspond to some of these graphs. The query execution starts with dereferencing of these graphs and the rest runs as usual. In more sophisticated case, the query is executed many times in a loop. Every execution produces a partial result. SPARQL processor checks for IRIs in the result such that resources with that IRIs may contain relevant data but not yet loaded into the DB.DBA.RDF_QUAD. After some iteration, the partial result is identical to the result of the previous iteration, because there's no more data to retrieve. As the last step, SPARQL processor builds the final result set. http://docs.openlinksw.com/virtuoso/rdfsparqlrule.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com Inference Rules & Reasoning 2009-11-16T14:26:59Z Inference Rules & Reasoning http://docs.openlinksw.com/virtuoso/rdfperformancetuning.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com Performance Tuning 2009-11-16T14:26:59Z Performance Tuning For RDF query performance, we have the following possible questions: http://docs.openlinksw.com/virtuoso/rdfnativestorageproviders.html virtuoso.docs@openlinksw.com virtuoso.docs@openlinksw.com RDF Data Access Providers (Drivers) 2009-11-16T14:26:59Z RDF Data Access Providers (Drivers)