xml-dev - Re: A certain difficulty

[David Megginson <david@megginson.com>]

Mark Birbeck <Mark.Birbeck@iedigital.net> writes:

> Hopefully my example shows that I'm coming at this from the other
> side; *my* creator might be "everyone who has designed a building"
> whilst *my mum's* creator is "everyone who has knitted a jumper".

That's only because you're loading too much meaning into the property
and forgetting about the class of the object it's attached to (Dublin
Core is guilty of the same thing).

> Of course we could say everyone must use "dc:Creator", but then how
> do I find everyone who ever knitted a jumper? Well of course I go to
> the knitting site that has used RDF to refer to subsets of other
> data, because they have a class called "Knitter".

Take a look at the class.  Consider the following:

  <rdf:RDF ...>

  <megg:Jumper rdf:about="http://www.foo.com/1">
    <dc:creator rdf:about="http://www.people.org/a"/>
  </megg:Jumper>

  <megg:Book rdf:about="http://www.amazon.com/ids/00002">
    <dc:creator rdf:about="http://www.people.org/b"/>
  </megg:Book>

  </rdf:RDF>

If you want to find every knitter but not every author, then simply
look only for dc:creator properties attached to an object of class
megg:Jumper.  The alternative is to create an endless stream of new
properties

  create
  sweaterCreator
  bookCreator
  carCreator
  webPageCreator
  cartoonCreator
  flyingSaucerCreator
  emailCreator
  badSmellCreator

etc.  Of course, you have no choice but to do this kind of thing when
you're using flat HTML <meta> tags, but RDF was designed specifically
to allow you to apply modern OO techniques to the problem.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/

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