created on Feb. 18, 2013, 4:07 p.m. by Hevok & updated on Feb. 18, 2013, 4:07 p.m. by Hevok
To explain a domain and its associated phenomena one need to create models of Classes and Relations on which one can later on make Facts about Individual in RDF. One need to think about Models from which Facts can be made.
If there is an Application Program and within this Program one can access and define RDF data, but one can only do this if the Application knows which terms and Classes to use. There are several problems associated with it. Does not know the term in advance and one needs some way to look this up? Are all terms that are used in the Program are really correct, is there something where one can look up to see if this is a correct usage of the data? Are there more logical Relations between the terms. These cannot be expressed in RDF, therefore a Schema Definition Language is required, the RDF Schema
which is officially the RDF Vocabulary Description Language
. The RDF Schema Language is a way to define an RDF Vocabulary and Classes as well as Relations between Classes.
RDF Schema
RDF Vocabulary Description Language
RDF defines a data model for the generation of RDF Statements and therefore provide the possibility to define classes and to instantiate these Classes, i.e. define individuals (instances of this Classes). This is done with the keyword <rdf:type>
. On the other-hand one can define new kinds of Properties and pose restriction on those Properties. There are also other kind of special Relations between classes like Class Hierarchies among Classes and Properties. What is a sub- and what a superclass or what is a sub and what a superproperties.
RDF Schema allows
Definition of classes
<rdf:types>
Definition of properties and restrictions
Definition of hierarchies
RDF Schema defines a data model for the definition of simple Ontologies (Knowledge Representations).
Via RDF Schema Ontologies RDF statements (Facts) can be expressed
More than XML:
(small) ontological agreement about modeling primitives
RDF Schema expresses kind of Knowledge like: Class and property Hierarchies Domain and range of Properties
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