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RE: A simple question on RDF Querying ...

From: Ron Daniel <RDaniel@DATAFUSION.net>
Date: Tue, 7 Dec 1999 12:05:19 -0800
Message-ID: <0D611E39F997D0119F9100A0C931315C60FF36@datafusionnt1>
To: Greg Karvounarakis <gregkar@csi.forth.gr>, RDF Interest Group <www-rdf-interest@w3.org>
Good question. Both behaviors (returning p2 vs. not returning
p2) would seem to be appropriate at different times. Here's
a couple of scenarios, assuming p1 is the Dublin Core creator

1) John Doe wants to search an RDF store of bibliographic information
for works written by his favorite author, J. Smith.  He searches
for statements where the predicate is dc:Creator and the object
is "J. Smith".  His database also searches for statements whose
predicate is known to be a subProperty of dc:Creator.

2) Jane Doe is analyzing the growth of the Dublin Core and its
mapping to other bibliographic standards. She searches her RDF
store for dc:Creator arcs and counts them. She also counts occurrences
of properties such as x:Illustrator that are subProperties of

I think a query language MUST provide functionality for the
second usage, and SHOULD provide an operator for the first case.


> -----Original Message-----
> From:	Greg Karvounarakis [SMTP:gregkar@csi.forth.gr]
> Sent:	Tuesday, December 07, 1999 8:02 AM
> To:	RDF Interest Group
> Subject:	A simple question on RDF Querying ...
> Hello everybody.
> I would like to have your opinion/comments on the following question:
> Suppose that I have an RDF schema like:
>                 [C1] ------p1------> [C2]
>                  /\        /\         /\
>                  ||        ||         ||
>                  ||        ||         ||
>                  ||        ||         ||
>                 [C3] ------p2------> [C4]
> p2: subPropertyOf p1
> C3, C4: subClassOf C1,C2 respectively.
> If a query requests the from and to values of the property p1
> (metadata instances), do you believe that the from and to values
> of its subProperty (p2) should also be returned?
> I would also appreciate any examples where the one case is 
> preferrable over the other (based on possible applications that
> you may have in mind).
> Thanx in advance
> Greg
Received on Tuesday, 7 December 1999 15:05:31 UTC

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