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RE: requirement: rdfs query (for lack of a better name...)

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 7 May 2004 12:28:47 -0500
Message-Id: <p06001f29bcc177866062@[10.0.100.76]>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>

>-------- Original Message --------
>>  From: public-rdf-dawg-request@w3.org <>
>>  Date: 06 May 2004 19:06
>>
>>  On Thu, May 06, 2004 at 12:52:40 -0500, Kendall Clark wrote:
>>  > Requirement
>>  > -----------
>>  > It should be possible to query the RDFS structure of an RDF graph to
>>  > find, for example, the parents and instances of a class or the class
>>  > tree.
>>  >
>>  > Discussion
>>  > ----------
>>  > I'm not sure whether this comes down, in the end, to a semantic
>>  > requirement or just a request for sugar for a particular kind of
>>  > query; but what my users need (and we have implemented in a really
>>  > ugly, API munging way) is the ability to ask for all the instances of
>>  > a class, all the parents of a class, and so on. Being able to do these
>>  > queries, and being able to do them "easily" (yes, I know, untestable,
>>  > but still...) is a real requirement for us.
>>
>>  Isn't that a question of what inference your RDFS engine supports?
>>
>>  If you do RDFS then (?x <rdfs:subclassOf> ?y) will give you
>>  all the superclasses of ?y in ?x.
>
>Agreed, it does - but sometimes the application wants to find direct
>subclass relationships

define 'direct'. (I don't think you will be able to in way that makes 
sense in an RDF context.)

Pat


>and sometimes all the transitive entailments. e.g.
>writing an editor. It is possible to want the both the direct relationship
>in one part of the query pattern and yet want RDFS inference elsewhere in
>the same query.
>
>>
>>  - Steve
>
>	Andy


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Received on Friday, 7 May 2004 13:28:49 GMT

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