Simon Cox wrote:
> Frank A. Roos wrote:
> >
> > It seems to me that DC.Type will always be present in a DC "record"
>
> Yes - if it is a "complete" record.
> But there are no mandatory fields in DC.
Sure, but I would not recommend leaving DC.Type out. For reasons of
interoperability DC.Type may be pivotal.
>
>
> > To generalize this thought, but maybe a bit off topic, although worthwhile I
> > think: it seems to me that each different type, is accompanied by a different
> > combination of the other DC fields. Maybe some fields are even mandatory to
> > make a type belong to a certain type (see for instance the "refer" and
> > "BiBTeX" bibliographic tools, where you have first to define type before
> > adding the (mandatory) fields to a record). So, type triggers a couple of
> > mandatory DC fields to be added to the DC record, that can be identified
> > beforehand as typical for that type. "Event" may at least need DC.coverage (in
> > most cases; does anybody know an example where an "event" does not have a
> > temporal or spatial aspect?), but undoubtedly also other fields.
> >
> > One may even want to categorize the needed fields for each type.
>
> I suspect that it would be possible to deduce a set of
> rules along these lines. That amounts to modelling the
> classes corresponding to the universe of "resources".
> Interesting, but almost impossible to do exhaustively.
> Hence, an early decision was made in DC to allow all elements
> to be present between zero and many times in all instances.
Sure. What we see now in DC implementations is a wide variety of interpretations.
For reasons of interoperability it might be useful, to have some notion of
categories of record for a type. This has been done before (see "refer" and
"BiBTeX; BTW, the types of these bibliographic tools have been used in the past for
identifcation of types by some implementers).
>
>
> --
> __________________________________________________
> Dr Simon Cox - Australian Geodynamics Cooperative Research Centre
> CSIRO Exploration & Mining, PO Box 437, Nedlands, WA 6009 Australia
> T: +61 8 9389 8421 F: +61 8 9389 1906 [log in to unmask]
> http://www.ned.dem.csiro.au/SimonCox/
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