rdfabout

rdf:about is an RDF/XML attribute used to identify the subject resource described by the containing RDF Description element. The value of rdf:about can be an absolute URI or a QName, which a RDF/XML processor expands to a full IRI using the document’s base URI or declared namespaces. By assigning a subject with rdf:about, the statements inside the element describe that named resource, enabling multiple properties to be attached to a single resource without creating an anonymous node.

In RDF/XML, rdf:about is commonly used on description elements to link properties to a specific resource. If the resource is intended to be a blank node, rdf:about is not used; blank nodes are described using blank node identifiers (such as rdf:nodeID or an anonymous description structure) instead.

rdf:ID is another mechanism related to subject identification. It constructs a URI by combining the document base with a local fragment specified by the rdf:ID value. Both rdf:about and rdf:ID identify the subject of the statements, but rdf:about accepts a full URI or a QName, while rdf:ID focuses on a fragment relative to the document base.

Example:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"

xmlns:ex="http://example.org/">

<rdf:Description rdf:about="http://example.org/Person123">

<ex:name>John Doe</ex:name>

<ex:age>30</ex:age>

</rdf:Description>

</rdf:RDF>

Rdf:about is specific to RDF/XML and does not appear in other RDF serializations such as Turtle or JSON-LD.