Hooking up with RDF
Ex-Homeland Security Department metadata chief Michael Daconta may have trumpeted the Resource Description Framework in his 2003 book The Semantic Web, but for most shops, the benefits of RDF have remained academic.
The good news is that RDF now has a powerful sponsor to help spur adoption. Oracle Corp. of Redwood Shores, Calif., has released a new database object type for storing RDF data, available with the Oracle Spatial Network Data Model, the company's software for managing graphs.
'RDF can be a very powerful tool when you're trying to infer across incomplete information,' said Xavier Lopez, director of spatial technologies for Oracle.
While XML encapsulates data within hierarchies, RDF represents the relationships among objects. A link, called the predicate, hooks a subject (i.e. 'John') to an object ('Suzie'), summarizing the relation between the two (John 'is a friend of' Suzie). A 'triple,' as this relationship is called, can be used to describe other triples.
'We've found that these RDF triples grow very large,' Lopez said. 'We have customers with millions of statements.' RDF could be particularly useful for searching. A Structured Query Language query to an RDF data store could return not only exact matches, but close companions.
The intelligence community has made early use of the Oracle RDF schema (for finding semantic matches and tracking social networks), Lopez said. So has the life sciences community (for mind-bendingly complex biological pathway analysis).
Other companies also are warming to RDF. Cogito Inc. of Draper, Utah, wove RDF into its recently released Cogito Knowledge Center, which maps relationships across databases. Users enter at one point and follow the trail to other objects, revealing undiscovered relationships, said William Donahoo, Cogito's vice president of product management and marketing.
Also on the RDF bandwagon is the CIO Council's Semantic Interoperability Community of Practice, which is rendering the Federal Enterprise Architecture's Data Reference Model in RDF, along with the Web Ontology Language.
According to the group's chairman, Brand Niemann, 'RDF offers developers a powerful toolkit for making statements and connecting those statements to derive meaning.'