RDF Schema

RDF Schema (Resource Description Framework Schema, variously abbreviated as RDFS, , RDF-S, or RDF/S) is a set of classes with certain properties using the RDF extensible knowledge representation data model, providing basic elements for the description of ontologies. It uses various forms of RDF vocabularies, intended to structure RDF resources. RDF and RDFS can be saved in a triplestore, then one can extract some knowledge from them using a query language, like SPARQL. The first version was published by the World-Wide Web Consortium (W3C) in April 1998, and the final W3C recommendation was released in February 2014. Many RDFS components are included in the more expressive Web Ontology Language (OWL). RDFS constructs are the RDFS classes, associated properties and utility properties built on the vocabulary of RDF. Represents the class of everything. All things described by RDF are resources. An rdfs:Class declares a resource as a class for other resources. A typical example of an rdfs:Class is in the Friend of a Friend (FOAF) vocabulary. An instance of is a resource that is linked to the class using the property, 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 is recursive: is the class of classes, and so it is an instance of itself. rdfs:Class rdf:type rdfs:Class The other classes described by the RDF and RDFS specifications are: literal values such as strings and integers. Property values such as textual strings are examples of RDF literals. Literals may be plain or typed. the class of datatypes. is both an instance of and a subclass of . Each instance of is a subclass of . the class of XML literal values. is an instance of (and thus a subclass of ). ' the class of properties. Properties are instances of the class and describe a relation between subject resources and object resources. When used as such a property is a predicate (see also RDF: reification). the rdfsdomain of an declares the class of the subject in a triple whose predicate is that property.