- The Resource Description Framework (RDF) is a language for representing information about resources in the World Wide Web.
- Originally RDF was primarily intended to represent metadata about Web resources, such as the title, author, and modification date of a Web page, copyright and licensing information about a Web document, or the availability schedule for some shared resource. However, by generalizing the concept of a "Web resource", RDF can also be used to represent information about things that can be identified on the Web, i.e. the semantic web.
2 Major RDF vocabularies
- Content syndication and social software
- RSS 1.0 which is not very popular, most RSS formats are not RDF since bloggers don't understand issues related to the semantic web :)
- FOAF Friends-of-a-friend vocabulary for person networks
- Semantic Web
3 RDF basics
At its core, RDF has a simple relational data model: Subject - Verb - Object or expressed differently Predicate (Subject, Object)
- Subject = The resource
- Object = Value
- Verb = Predicate = propriety = relation of the subjet with the object
Here is a typical RDF fragment
<?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:mon_schema="http://tecfa.unige.ch/lib/mon_schema" > <rdf:Description rdf:about="http://tecfa.unige.ch/perso/staf/lattion/"> <mon_schema:Creator>Stéphane Lattion</mon_schema:Creator> </rdf:Description> </rdf:RDF>
It expresses a relation like this:
4 RDF and the semantic web
4.1 The RDF Software stack
4.2 The RDF bus
5 Turtle syntax
Since XML/RDF code is some verbose, writing it manually is fairly time consuming. The W3C team proposes a "textual syntax for RDF called Turtle that allows RDF graphs to be completely written in a compact and natural text form, with abbreviations for common usage patterns and datatypes" (Turtle - Terse RDF Triple Language, retrieved 15:31, 10 March 2008 (MET)).
<?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:ex="http://example.org/stuff/1.0/"> <rdf:Description rdf:about="http://www.w3.org/TR/rdf-syntax-grammar" dc:title="RDF/XML Syntax Specification (Revised)"> <ex:editor> <rdf:Description ex:fullName="Dave Beckett"> <ex:homePage rdf:resource="http://purl.org/net/dajobe/" /> </rdf:Description> </ex:editor> </rdf:Description> </rdf:RDF>
becomes in turtle syntax:
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix dc: <http://purl.org/dc/elements/1.1/> . @prefix ex: <http://example.org/stuff/1.0/> . <http://www.w3.org/TR/rdf-syntax-grammar> dc:title "RDF/XML Syntax Specification (Revised)" ; ex:editor [ ex:fullname "Dave Beckett"; ex:homePage <http://purl.org/net/dajobe/> ] .
- Resource Description Framework (RDF) Overview
- Resource Description Framework (RDF): Concepts and Abstract Syntax, W3C Recommendation 10 February 2004
- Resource Description Framework (RDF) Model and Syntax.
- RDF Semantics, W3C Recommendation 10 February 2004 (rather difficult reading).
- RDF/XML Syntax Specification, W3C Recommendation 10 February 2004.
- RDF Vocabulary Description Language 1.0: RDF Schema, W3C Recommendation 10 February 2004
- Turtle - Terse RDF Triple Language
- RDF Namespaces
- RDF and XHTML
- OWL Web Ontology Language Overview, W3C Recommendation 10 February 2004.
- OWL Web Ontology Language Guide, W3C Recommendation 10 February 2004
- OWL Web Ontology Language Semantics and Abstract Syntax, W3C Recommendation 10 February 2004
- Dean M., Schreiber G (Editors); van Harmelen F., Hendler J., Horrocks I., McGuinness D.L., Patel-Schneider P.F., Stein L.A. (Authors), OWL Web Ontology Language Reference, W3C Recommendation, 10 February 2004. HTML
- Other RDF Applications
- SPARQL Query Language for RDF (W3C Recommendation, 15 January 2008)
- PICS (Platform for Internet Content Selection)
- SKOS Simple Knowledge Organization System (W3C WD Jan 2008)
- Mozilla's RDF pointers
- Oasis Resource Description Framework (RDF)
- W3C Data Formats A older (1997) note on the planned XML-centered framework
- Chris Waterson, RDF in Fifty Words or Less, Mozilla Magazine.
6.3 On-line validation
6.5 Various to sort out
- Supercharging WSDL with RDF Managing structured Web service metadata article by Uche Obbuji
- Rudolf: RDFViz Exploring tools for RDF Graph Visualisation by Dan Brickely, project page.
- Eric Miller An Introductionto the Resource Description Framework (1998), D-Lib Magazine May 1998, ISSN 1082-9873, HTML
- Manola Frank and Eric Miller (2004). RDF Primer, W3C Recommendation 10 February 2004, W3C.