RDF Language

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An RDF Language is a W3C metadata modeling language for describing the interrelationships between two web resources in the form of subject-predicate-object RDF triples.



  • (Wikipedia, 2011) http://en.wikipedia.org/wiki/Resource_Description_Framework
    • The Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata data model. It has come to be used as a general method for conceptual description or modeling of information that is implemented in web resources, using a variety of syntax formats.

      The RDF data model[1] is similar to classic conceptual modeling approaches such as Entity-Relationship or Class diagrams, as it is based upon the idea of making statements about resources (in particular Web resources) in the form of subject-predicate-object expressions. These expressions are known as triples in RDF terminology. The subject denotes the resource, and the predicate denotes traits or aspects of the resource and expresses a relationship between the subject and the object. For example, one way to represent the notion "The sky has the color blue" in RDF is as the triple: a subject denoting "the sky", a predicate denoting "has the color", and an object denoting "blue". RDF is an abstract model with several serialization formats (i.e., file formats), and so the particular way in which a resource or triple is encoded varies from format to format.

  1. http://www.w3.org/TR/PR-rdf-syntax/ "Resource Description Framework (RDF) Model and Syntax Specification"


  • (W3, 2011) ⇒ http://www.w3.org/RDF/
    • RDF is a standard model for data interchange on the Web. RDF has features that facilitate data merging even if the underlying schemas differ, and it specifically supports the evolution of schemas over time without requiring all the data consumers to be changed.
    • RDF extends the linking structure of the Web to use URIs to name the relationship between things as well as the two ends of the link (this is usually referred to as a “triple”). Using this simple model, it allows structured and semi-structured data to be mixed, exposed, and shared across different applications.
    • This linking structure forms a directed, labeled graph, where the edges represent the named link between two resources, represented by the graph nodes. This graph view is the easiest possible mental model for RDF and is often used in easy-to-understand visual explanations.



  • (Obitko, 2007) ⇒ Marek Obitko. (2007). “Translations Between Ontologies in Multi-agent Systems - Ontology Operations].” PhD Thesis, Czech Technical University http://www.obitko.com/tutorials/ontologies-semantic-web/rdf-graph-and-syntax.html
    • These triples together form RDF graph. A graph with the triples from figures showing triple and showing literal and with some additional triples are shown in the figure below. The top triple uses type as a predicate from RDF vocabulary to express that joesmith is of type Person.

      A normative syntax for serializing RDF is RDF/XML. The RDF graph from the figure below is written in RDF/XML as follows. Note that it uses XML namespaces with prefixes defined in the beginning of the XML document(...)

      RDF/XML is a normative syntax, however, other serialization formats are used as well. The TURTLE and N3 syntax is less verbose than RDF/XML and so is quite popular. The Notation 3 (N3) is designed as a readable language for data on the Web that goes beyond RDF (it contains logical extensions and rules). The Terse RDF Triple Language (TURTLE) is a RDF-only subset of N3. For the purposes of this text these two languages are interchangeable.