Karen Coyle wrote:
The above looks really odd to me -- I'm not at all sure that you can
use the class Agent in that way.... I was of the impression that
classes are used in metadata definitions, but not in instances. Am I
wrong?
I'll answer my own question: yes, I'm wrong. Here's an example from the
RDF primer:
<?xml version="1.0"?>
<!DOCTYPE rdf:RDF [<!ENTITY xsd "http://www.w3.org/2001/XMLSchema#";>]>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
xmlns:ex="http://example.org/schemas/vehicles#";
xml:base="http://example.org/things";>
<ex:PassengerVehicle rdf:ID="johnSmithsCar">
<ex:registeredTo rdf:resource="http://www.example.org/staffid/85740"/>
<ex:rearSeatLegRoom
rdf:datatype="&xsd;integer">127</ex:rearSeatLegRoom>
<ex:primaryDriver rdf:resource="http://www.example.org/staffid/85740"/>
</ex:PassengerVehicle>
</rdf:RDF>
So <frbr:Work> and <frbr:Expression> also appear to work as classes, if
that's what you intend. I still can't wrap my head around what they are
*functionally.* As far as I can tell, classes give you categories, but
don't themselves have properties, so they don't function like the class
in OOP. At best, it seems that you get:
A is of class X
B is of class X
C is of class X
therefore: class X = A, B, C
But if someone else states that
B is of class Y
then my question is: has B changed? In other words, is B of class X the
same as B of class Y? (Assuming that both B's have the same URI.). Again
this seems to get back to flexible v. specific. The more flexible you
want to be, the more you depend on context. The more specific you are,
the more your metadata is independent of context. So for me it comes
down to functionality, which is how much context do I want to carry
around in order to make sense of my metadata? I think for the purposes
of open data exchange, context adds overhead.
kc
--
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Karen Coyle / Digital Library Consultant
kco...@kcoyle.net http://www.kcoyle.net
ph.: 510-540-7596 skype: kcoylenet
fx.: 510-848-3913
mo.: 510-435-8234
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