about vs. ID

From: Frank van Harmelen (Frank.van.Harmelen@cs.vu.nl)
Date: 12/25/00


Another point resulting from working on the DAML+OIL walkthrough:

I have been told that for RDF, there is no difference between writing:
  <rdfs:Class rdf:ID="Animal"/>
and
  <rdfs:Class rdf:about="#Animal/>

However, I have the impression that we have been (silently?) exploiting this non-existent distinction to indicate that the first is the "initial" introduction/definition of the Class, and that the second is an "additional" statement about a previously defined class. 

I have the feeling that this is ill-conceived. After all, who is to say which of these statements is processed first? They might even live in different files (with a suitably amended URI for the value of the about attribute). 

I was told that a better way of thinking is that all such statements just add to what we know about the class Animal, without giving any one of them a special status. Is there a way to make the situation more symmetrical? How about replacing all use of ID="classname" by about="#classname", as a matter of style? 

Frank.
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