Web Ontology Language (OWL)
OWL is the acronym for Web Ontology Language. (Yes, it’s a little backward, but OWL reads better than WOL!) OWL lets developers define classes over which to define relationships, specify range of values, and indicate cardinality. The OWL specification provides numerous tutorial examples of how to use OWL. For example, the following OWL construct sets the properties of wine:
<owl:ObjectProperty rdf:ID="madeFromGrape"> <rdfs:domain rdf:resource="#Wine"/> <rdfs:range rdf:resource="#WineGrape"/> </owl:ObjectProperty>
Translating this OWL statement into English, we get "Wine is made from grapes." In effect, we’re declaring that we have a property madeFromGrape that applies to the thing called Wine and that the kind of grapes that can be used to make wine come from WineGrapes. If this example seems rather complex and difficult to parse, don’t worry—OWL isn’t made for human consumption, but rather to be amenable to computer manipulation.