Main RDFS constructs
Classes and subclasses
- rdfs:Class allows to declare a resource as a class for other resources.
Typical example of an rdfs:Class is foaf:Person in the FOAF vocabulary. An instance of foaf:Person is a resource linked to the class using an rdf:type predicate, such as in the following formal expression of the natural language sentence : 'John is a Person'.
ex:John rdf:type foaf:Person
The definition of rdfs:Class is recursive: rdfs:Class is the rdfs:Class of any rdfs:Class.
- rdfs:subClassOf allows to declare hierarchies of classes.
For example, the following declares that 'Every Person is an Agent':
foaf:Person rdfs:subClassOf foaf:Agent
Hierarchies of classes support inheritance of a property domain and range (see definitions in next section) from a class to its subclasses.
Property domain and range
- rdfs:domain of an rdf:property declares the class of the subject in a triple using this property as predicate.
- rdfs:range of an rdf:property declares the class or datatype of the object in a triple using this property as predicate.
For example the following declarations are used to express that the property ex:employer is linking a subject which is a foaf:Person, to an object which is a foaf:Organization
ex:employer rdfs:domain foaf:Person
ex:employer rdfs:range foaf:Organization
Given the previous declarations, in the following triple, ex:John is necessarily a foaf:Person, and ex:CompanyX is necessarily a foaf:Organization
ex:John ex:employer ex:CompanyX
See also
- SPARQL Query Language for RDF
References
External links
This article is licensed under the GNU Free Documentation License.
Last updated on Monday October 06, 2008 at 06:33:13 PDT (GMT -0700)
View this article at Wikipedia.org - Edit this article at Wikipedia.org - Donate to the Wikimedia Foundation
Main RDFS constructs
Classes and subclasses
- rdfs:Class allows to declare a resource as a class for other resources.
Typical example of an rdfs:Class is foaf:Person in the FOAF vocabulary. An instance of foaf:Person is a resource linked to the class using an rdf:type predicate, such as in the following formal expression of the natural language sentence : 'John is a Person'.
ex:John rdf:type foaf:Person
The definition of rdfs:Class is recursive: rdfs:Class is the rdfs:Class of any rdfs:Class.
- rdfs:subClassOf allows to declare hierarchies of classes.
For example, the following declares that 'Every Person is an Agent':
foaf:Person rdfs:subClassOf foaf:Agent
Hierarchies of classes support inheritance of a property domain and range (see definitions in next section) from a class to its subclasses.
Property domain and range
- rdfs:domain of an rdf:property declares the class of the subject in a triple using this property as predicate.
- rdfs:range of an rdf:property declares the class or datatype of the object in a triple using this property as predicate.
For example the following declarations are used to express that the property ex:employer is linking a subject which is a foaf:Person, to an object which is a foaf:Organization
ex:employer rdfs:domain foaf:Person
ex:employer rdfs:range foaf:Organization
Given the previous declarations, in the following triple, ex:John is necessarily a foaf:Person, and ex:CompanyX is necessarily a foaf:Organization
ex:John ex:employer ex:CompanyX
See also
- SPARQL Query Language for RDF
References
External links
This article is licensed under the GNU Free Documentation License.
Last updated on Monday October 06, 2008 at 06:33:13 PDT (GMT -0700)
View this article at Wikipedia.org - Edit this article at Wikipedia.org - Donate to the Wikimedia Foundation
|
|
|
|
|
|
|
|
|
|
Copyright © 2009, Dictionary.com, LLC. All rights reserved.
