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The Semantic Web, Semantic Web Services and more…

RDF Schema (RDFS) Example

Posted by Aditya Thatte on November 16, 2008

RDF is a mechanism to describe information on the web.RDF Schema ( RDFS ) adds vocabulary to express information in the form of classes and subclasses and the relationship between them. RDF also defines properties associated with classes.

A relationship between two things / entities can be represented by a class. A list of all RDF classes and properties can be found at http://www.w3.org/TR/rdf-schema/.

Let us consider an example of RDF and RDFS layers.

Statement : Aditya Thatte stays in Pune

The schema for this statement will contain the following classes and propertiesrdf_rdfs

For the statement ” Aditya Thatte stays in Pune ” , the RDF triple is ( Aditya Thatte , stays in , Pune)

This  can be mapped to a schema which contains the classes ” Citizen ” and ” Country”. A Citizen “abc”

stays in a country ” X” , then “X’ also involves “abc”.

The class citizen has subclasses “Voting citizen ” and ” non voting citizen” and the country class has subclasses ” states ” which inturn has subclasses ” city ” , “town” , ” taluka” represented by the “subclassof ” property.

The rectangle represents properties, ellipses in the RDFS layer represents classes while ellipses in the RDF layer represents instances. The domain and range enforce constraints on the subject and objects of a property.

So, the above diagram suggests that the subject ( Aditya Thatte ) is a “type” of voting citizen , object (Pune) is a “type” of a city and the relationship between them is ” stays in” or “resides in” .

Thus, RDFS expresses vocabulary in the form of classes and properties.

References : Thinking on the web – H.Peter Alesso, Craig F. Smith

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