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Re: xml without rdf, but with an ontology [0]

From: Ian Davis <iand@internetalchemy.org>
Date: Fri, 14 Jan 2005 14:27:33 +0000
Message-ID: <41E7D6D5.7060604@internetalchemy.org>
To: atom-owl@googlegroups.com
CC: jsled@asynchronous.org, www-rdf-interest@w3.org, bloged <users@bloged.dev.java.net>

On 14/01/2005 12:51, Henry Story wrote:
> 
> Thanks Josh,
> 
> I like your answers to Ian's questions :-)
Me too :)


> I don't think any heuristics are needed. Just an ontology for the
> tags and attributes plus a systematic way to map xml into graph space
> which I have described in this thread.

The point I was attempting to get across in my original email was that I 
could think of no heuristic that would give a consistent mapping using 
only the instance document. The mappings that Josh came up with aren't 
consistent: I would need to use a different query against the triple 
store for each form to extract the content (for display, perhaps).

With some kind of schema annotation one could declare that the content 
of <extension> is always an XMLLiteral.

For the format that provoked this discussion (Atom) it's expected that 
authors will extend the format in new and exciting ways. Giving the 
parser knowledge of all possible extensions up front in the form of a 
schema for each is rather defeating the point of the mapping.

So, there need to be some sort of structural rules that define what 
types of triples should be produced. These rules should be consistent 
and work from the instance document. For the specific case of Atom the 
following suggested equivilences between markup and NTriples might serve:

1. Element is empty.

<item>
   <ex:extension/>
</item>

_:item a atom:item .
_:item ex:extension _:ext .

2. Element is empty, but has attributes -> Attributes are assumed to be 
properties.

<item>
   <ex:extension ex:att="xxx"/>
</item>

_:item a atom:item .
_:item ex:extension _:ext .
_:ext ex:att "xxx" .


3. Element has character content -> Content becomes rdf:value of anon node

<item>
   <ex:extension>xxx</ex:extension>
</item>

_:item a atom:item .
_:item ex:extension _:ext .
_:ext rdf:value "xxx" .

4. Element has mixed content -> Content becomes rdf:value as above

<item>
   <ex:extension>xxx<other/></ex:extension>
</item>

_:item a atom:item .
_:item ex:extension _:ext .
_:ext rdf:value "xxx<other/>" .

5. Element has element content -> Content still becomes rdf:value as above

<item>
   <ex:extension><other/></ex:extension>
</item>

_:item a atom:item .
_:item ex:extension _:ext .
_:ext rdf:value "<other/>" .

6. Element has content and attributes.

<item>
   <ex:extension ex:att="xxx">xxx<other/></ex:extension>
</item>

_:item a atom:item .
_:item ex:extension _:ext .
_:ext rdf:value "xxx<other/>" .
_:ext ex:att "xxx" .


Is this worth writing up as a Pace for Atom?

Ian
Received on Friday, 14 January 2005 14:27:36 GMT

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