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Status: stable
Last release: 6.2 (2010/09/15)
License: Commercial & LGPL
Language: C
Affiliation: OpenLink
Web resources

Virtuoso RDF Views[edit]

It is a known fact that the majority of the worlds data resides in relational databases which historically is hidden from public access behind corporate firewalls. If this data is to be available as part of the emerging Linked Data paradigm making it available for public access then schemes need to be devised for mapping this data to RDF for deployment as Linked Data. Such a scheme must provide adequate performance, scalability, reliability and accuracy of data mapping to provide a viable solution.

Making use of its Existing robust and high performance virtual/federated database engine, with the Virtuoso Universal Server it was possible to build a SPARQL to SQL relational mapping layer into the server which is known as RDF Views. The term RDF Views is a moniker for the two key technologies at the heart of Virtuoso's RDF support, namely its RDF Meta Schema and declarative Meta Schema Language for mapping SQL data to RDF ontologies. The mapping is dynamic, consequently changes to the underlying data are reflected immediately in the RDF representation with no changes required to the underlying relational schema, thus minimising disruption to a critical company asset.

Recent enhancement in Virtuoso RDF Views in 2010 enable the materialization and synchronization of the RDF View generated triples with the RDF Quad store using RDB2RDF Triggers. This enables standard SPARQL operations like inferencing, facet browsing and others to be performed on the materialized triples. To perform this task the required RDB data objects must first be linked into Virtuoso, from which local incrementally snapshot replicated copies can be created and automatically kept in sync. A standard set of RDF Views can then be create of these locally replicated objects on which a set of RDB2RDF Triggers are created for converting the local RDF Views to physical triples and keeping both sync.