Archive for the ‘R2ML’ Category

Relational Data to RDF [Bridge to No Where?]

Sunday, October 21st, 2012

Transforming Relational Data to RDF – R2RML Becomes Official W3C Recommendation by Eric Franzon.

From the post:

Today, the World Wide Web Consortium announced that R2RML has achieved Recommendation status. As stated on the W3C website, R2RML is “a language for expressing customized mappings from relational databases to RDF datasets. Such mappings provide the ability to view existing relational data in the RDF data model, expressed in a structure and target vocabulary of the mapping author’s choice.” In the life cycle of W3C standards creation, today’s announcement means that the specifications have gone through extensive community review and revision and that R2RML is now considered stable enough for wide-spread distribution in commodity software.

Richard Cyganiak, one of the Recommendation’s editors, explained why R2RML is so important. “In the early days of the Semantic Web effort, we’ve tried to convert the whole world to RDF and OWL. This clearly hasn’t worked. Most data lives in entrenched non-RDF systems, and that’s not likely to change.”

“That’s why technologies that map existing data formats to RDF are so important,” he continued. “R2RML builds a bridge between the vast amounts of existing data that lives in SQL databases and the SPARQL world. Having a standard for this makes SPARQL even more useful than it already is, because it can more easily access lots of valuable existing data. It also means that database-to-RDF middleware implementations can be more easily compared, which will create pressure on both open-source and commercial vendors, and will increase the level of play in the entire field.” (emphasis added)

If most data resides in non-RDF systems, what do I gain by converting it into RDF for querying with SPARQL?

Some possible costs:

  • Planning the conversion from non-RDF to RDF system
  • Debugging the conversion (unless it is trivial, the few conversions won’t be right)
  • Developing the SPARQL queries
  • Debugging the SPARQL queries
  • Updating the conversion if new data is added to the source
  • Testing the SPARQL query against updated data
  • Maintenance of the source and target RDF systems (unless pushing SPARQL is a way to urge conversion from relational system)

Or to put it another way, if most data is still on non-RDF data stores, why do I need a bridge to SPARQL world?

Of is this a Sarah Palin bridge to no where?

RDFa1.1 and R2ML

Tuesday, April 12th, 2011

RDFa1.1 and R2ML

A presentation from November, 2010 at the Benelux Semantic Web Meetup, Amsterdam by Ivan Herman of the W3C.

Nothing startling if you have kept up with RDF/RDFa work at the W3C but a good summary if you have not.