W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

Re: DATATYPES: mental dump.

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Tue, 13 Nov 2001 12:03:55 -0600
Message-Id: <p05101036b8170e0ea8f5@[65.212.118.147]>
To: Sergey Melnik <melnik@db.stanford.edu>
Cc: w3c-rdfcore-wg@w3.org
>Pat,
>
>thanks for a great "dump". I'm going to work it into the document almost
>completely, if you don't mind.

Sure, that's what I wrote it for.

>I'm thinking of a running example that can be used to illustrate the
>different proposals and modeling options.

Good idea.

>My current shot at it is:
>
>http://WWW-DB.Stanford.EDU/~melnik/rdf/datatyping/fig/motivating_example.gif
>
>It shows an interpretation, which can be encoded in many different ways,
>e.g. as:

OK, though I think we need to be careful about having the strings in 
the interpretation, since the X and P schemes probably won't have 
anything denoting those.

Also, this can be described in several different ways even within a 
given datatyping-syntax option, so we need to be careful not to get 
confused with alternative ways of describing this structure in RDF.

>_Robby ageMonthDecimal "12"
>_Robby weightKgDecimal "14"
>_Jenny weightKgOctal   "14"
>_Jenny ageYearsDecimal "1"
>
>in P(++) scheme.

One possibility, though eg (In ascii-graph-art)

_Robby ---weightKg--> "14" ---rdf:type--> xsd:decimal

would be more in the P++ style, and

_Robby weightKg "14" .
weightKg rdfs:range xsd:decimal .

more in the P style.

>The advantage of starting with an interpretation instead of a piece of
>syntax is that is it possible to refer to the different entities in the
>domain of discourse directly and tell how the corresponding pieces of
>syntax are mapped onto them (for example, "12" and "1" above are
>interpreted as entity d1 in the figure).

Ah, I see. That seems rather odd to me, I confess, as it assumes that 
durations are the value space of a datatyping scheme. I would have 
guessed that it was more likely that numbers - the n1-3 in your 
figure - would be in the literal value space, and that things like 
inYears and weightKg would be rdf properties.

I guess the moral is that part of the 'model' must be what datatyping 
schemes are supposed to be in use.

Pat

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Received on Tuesday, 13 November 2001 13:03:38 EST

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