• RDF Schema provides constructs to define vocabularies for the Web
• The RDF Schema elements are in the namespace: http://www.w3.org/2000/01/rdf-schema#

RDF Schema Classes

• rdfs:Resource - The class of all things
• rdfs:Class - The class of all classes
• rdfs:Literal - The class of all data literals (or data values), subsuming plain and typed literals
• rdfs:XMLLiteral - The class of all literals with XML syntax
• rdfs:Datatype - The class of all datatypes

RDF Schema Properties

• rdfs:subClassOf
• rdfs:subPropertyOf
• rdfs:domain
• rdfs:range
• rdfs:seeAlso
• rdfs:isDefinedBy
• rdfs:comment
• rdfs:label

Defining Properties

<rdf:Description rdf:ID="ex:name">
 <rdf:type rdf:resource="rdf:Property"/>
</rdf:Description>

or

<rdf:Property rdf:ID="ex:name"/>

or

ex:name rdf:type rdf:Property

Defining Properties with Domain and Range

... helps to avoid typing mistakes.

<rdf:Property rdf:ID="p:age">
 <rdfs:domain rdf:resource="uni:Employee"/>
 <rdfs:range rdf:resource="xs:integer"/>
</rdf:Property>

In the above example you can see age values as typed literals.

Defining a Data-Valued Property without a Specific Datatype

Relationships Between Core Classes and Properties

• rdfs:subClassOf and rdfs:subPropertyOf are transitive, by definition
• rdfs:Class is a subclass of rdfs:Resource i.e. the following axiom holds:

rdfs:Class rdfs:subClassOf rdfs:resource.

• Because everything is a resource rdfs:Resource is an instance of rdfs:Class i.e.

rdfs:Resource rdf:type rdfs:Class.

• rdfs:Resource is the class of all resources

rdfs:Resource rdf:type rdfs:Resource.

• Every class is an instance of rdfs:Class. Consequently rdfs:Classis an instance of itself

rdfs:Class rdf:type rdfs:Class

References

• RDF Vocabulary Description Language 1.0: RDF Schema W3C Recommendation 10 February 2004, http://www.w3.org/TR/rdf-schema/