- From: Dan Brickley <danbri@w3.org>
- Date: Fri, 12 Mar 2004 10:48:45 -0500
- To: "Miles, AJ (Alistair) " <A.J.Miles@rl.ac.uk>
- Cc: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>
* Miles, AJ (Alistair) <A.J.Miles@rl.ac.uk> [2004-03-12 15:23-0000] > > Can anyone tell me what's the fundamental difference between these two > properties? dc:subject is a relationship between a document-like-thing and some kind of identifier for a topic/subject that the document's contents cover (could be a Literal or a Resource, in RDF-ese). foaf:topic is a relationship between a Document and a thing that the document is about. It is more direct than dc:subject, and allows any RDF statements to be used when identifying the thing that the document is about. So, for a document about me. Imagine Dewey Decimal Classification had a subject code for me, Dan Brickley... "ddc-000.1234567", there would be a dc:subject property of my homepage with that as its value (perhaps shoe-horned into URI space somehow, eg. via a purl.org URI). By contrast, you'd see foaf:topic used in any of several ways: <Document rdf:about="http://rdfweb.org/people/danbri/"> <topic> <Person foaf:name="Dan Brickley" foaf:aimChatID="danbri_2002"/> </topic> </Document> ...is a way of saying "such and so document has as a topic a thing that has a foaf:name "Dan Brickley" and an aimChatID of "danbri_2002". So foaf:topic is both direct and flexible, but does not directly use library-style classification schemes, thesauri etc. It is good for referencing things that are easily identified via RDF descriptions. dc:subject always indirects via a resource that is a subject-code (or similar), whereas foaf:topic directly references the thing that the subject-code is a code for. Hope this makes some kind of sense! Dan
Received on Friday, 12 March 2004 10:48:45 UTC