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Datatype

From: Shelley Powers <shelleyp@burningbird.net>
Date: Mon, 25 Nov 2002 16:47:07 -0600
To: <www-rdf-comments@w3.org>
Message-ID: <AOEKLHGMHIHGNIBEDMNMEEKHDFAA.shelleyp@burningbird.net>


>
> > Also, Frank, a question on dates: I've seen references to
> > multiple documents about what date types are supported. I imagine
> > that we can use RDFS to provide instructions to consumers of our
> > vocabulary as to which date format is being supported. Or do we
> > use rdf:datatype? There's quite a bit of discussion on data
> > types, but it seems disjointed. I can't help thinking that the
> > primer could bring this together.
> >
> > Also question: you all aren't really going to support values of
> > '"1999-08-16"^^xsd:date', are you? No offense, but this horrid.
> > No offense again, but this is absolutely horrid. What's wrong
> > with using RDFS to define the data type, rather than making the
> > value into an intelligent value (ie data type is incorporated
> > into the instance, rather than the vocabulary definition)?
> > Embedding intelligence into values is the worst thing you can do
> > for a data model, regardless of model meta-structure.
> >
> > This is a broader question to group, or a request clarification
> > if I'm reading this wrong. I'm hoping I'm reading this wrong.
> >
> > Shelley
> >
>
> As a point of clarification on this, it isn't the format that
> bothers me -- it's the tying the datatype to instances rather
> than vocabulary. I know that RDF/xml uses rdf:datatype rather
> than  '"1999-08-16"^^xsd:date', but this again attaches the
> datatype to the instance, rather than the vocabulary. So, I could
> use http://www.w3.org/2001/XMLSchema#date for a date column that
> has data of 199-10-10, and use
http://www.w3.org/2001/XMLSchema#integer for another instance of the
vocabulary (another document), and this means time in seconds from a set
date. Both are accurate, but neither is compatible.

See the problems?

However, if we attach the rdf:datatype to the definition of the vocabulary
itself rather than any specific document, then the creators of the
vocabulary can say that this property takes integers representing number of
seconds since whatever. And all instances (documents) based on the
vocabulary would be compatible.

Sorry, I know this is my strong data background talking, but I can see a
nightmare in the making with this one.

Shelley
Received on Monday, 25 November 2002 17:48:20 GMT

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