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Re: Is there a way to specify a data format based on RDF ?

From: Paul Gearon <gearon@ieee.org>
Date: Wed, 13 Jun 2007 21:02:03 -0500
Message-Id: <E6E7EDF4-ECF8-4F7B-B172-C4683F285A39@ieee.org>
To: SW-forum <semantic-web@w3.org>

On Jun 13, 2007, at 5:33 PM, Kjetil Kjernsmo wrote:

> On Wednesday 13 June 2007, Andrea Splendiani wrote:
>> I want to be able to specify what it should contain, like: a valid
>> document must have at least one address.
> For that kind of thing, you would probably want to look into the
> cardinality constraints of OWL. It may do what you want.

This crossed my mind as well, but reading between the lines I don't  
think it will suit.

I'm guessing that Andrea needs to *enforce* a cardinality constraint  
on her address as 1.  While you can describe this, there's no way to  
enforce that an address entry will appear in RDF.  It's that whole  
open-world assumption thing.

Likewise, it's also only possible to ensure that the maximum  
cardinality doesn't exceed 1 by putting in a lot of data to describe  
that all the addresses are different from each other.  (You also  
don't want to sidestep that requirement by making the canonical text  
representation of an address inverseFunctional on the address, as  
that puts you into OWL Full.)

RDF just isn't well suited for describing structures that MUST  
include a particular field.  (You *can* do this, but then you're  
ignoring RDF's semantics, and just treating it as a weird database).

Paul Gearon
Received on Thursday, 14 June 2007 02:02:12 UTC

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