W3C home > Mailing lists > Public > www-rdf-interest@w3.org > October 2000

Re: A DTD for the abstract RDF model

From: Jonas Liljegren <jonas@liljegren.org>
Date: 09 Oct 2000 16:38:01 +0200
To: Graham Klyne <GK@Dial.pipex.com>
Cc: Tom Van Eetvelde <tom.van_eetvelde@alcatel.be>, www-rdf-interest@w3.org
Message-ID: <87zoke2i7q.fsf@jonas.rit.se>
Graham Klyne <GK@Dial.pipex.com> writes:

> I think I can accept the broad thrust, but maybe have problems with
> a few details.
> If I understand correctly, you replace a literal with a resource
> with properties, as in:
>    <Description>
>      <value>98</value>
>      <type resource="http://www.datatypes.org/useful_types#Integer"/>
>    </Description>
> so that the 'value' attribute has the literal value as an object, the 'type'
> indicates a subtype of literal.  Attributes of the property referencing the
> literal, such as xml:lang, can be represented as properties on the literal
> resource.

Yes.  And this is based on the RDF M&S and RDF Schema.  The M&S have a
section talking about the value property, used to specify the unit for
a value, and other things.  The RDF Schema defines the Literal class.

> Given the above, what (if anything) is to prevent:
>    <Description>
>      <value>
>        <Description>
>          <value>98</value>
>          <type resource="http://www.datatypes.org/useful_types#Integer"/>
>        </Description>
>      </value>
>      <type resource="http://www.datatypes.org/useful_types#Integer"/>
>    </Description>
> ?  i.e. repeated substitution of the literal with its interpretation as a
> resource.  Does this matter?  Maybe not.

Exactly. But that should only be a syntax thing.  We can now simply
remove the literal from the DLG. ... But the thing here is that that's
optional.  Everything will work the same way either way.

> When you wrote:
> >Age as a resource:
> >
> ><Description about="http://give.me/a.number">
> >     <type resource="http://www.datatypes.org/useful_types#Integer"/>
> ></Description>
> I'm not sure how you mean the value "98" to be conveyed.

The number will be conveyd by the implementing software, outside the
realm of RDF.  Either by accessing some database or internal
representation to get the value associated with the resource.  Or maby
by accessing the page http://give.me/a.number and displaying the
retrieved result.  

The method of accessing the actual value will be dependent on the
implementing software.  Let's say that the resouce
http://give.me/mp3.file represents a mp3 music file.  We could say
that the URI http://give.me/mp3.file#title will represent the title of
the track, stored inside it.  A mp3-aware RDF program could retrieve
the actual title by parsing the mp3 file.

For more about all sorts of RDF things. Check out the mail archive for
the Wraf project:

/ Jonas  -  http://jonas.liljegren.org/myself/en/index.html
Received on Monday, 9 October 2000 10:34:45 UTC

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