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RE: "OR" in Schema spec

From: Milla Makelainen <millam@nortelnetworks.com>
Date: Thu, 6 May 1999 10:38:30 +0100
Message-ID: <A3C638423CF7D211AA2F00204840075B221612@zhard00e.europe.nortel.com>
To: "'Dan Brickley'" <Daniel.Brickley@bristol.ac.uk>
Cc: "'www-rdf-comments@w3.org'" <www-rdf-comments@w3.org>
Thanks Dan,

> eg.	pet -range-> Pet
>	Cat -subClassOf->Pet
>	Dog -subClassOf->Pet
>	Poodle -subClassOf->Pet

However, this is not quite what I'm looking for. In this model I don't know
that Poodle is a Dog (because dog has nothing to do with poodle), only that
it's a pet and that dogs and cats are pets as well. 

If the last "Pet" is typo and you mean "Dog" it makes more sense, but still
I'm not quite convinced. It works from the root down - I know that poodle is
a dog and dog is a pet, but I still don't know anything about what pet can
be in that level. 

Is there a way around this?

Cheers,

Milla

Milla Makelainen
Smart Network Technology, Nortel Networks
email: millam@nortelnetworks.com
tel. +44 (0) 1279 403270
mobile +44 (0) 780 149 5538
-- "Wisdom is being able to cope"

This message may contain information proprietary to Nortel Networks, so
any unauthorised disclosure, copying or distribution of its contents is
strictly prohibited.


-----Original Message-----
From: Dan Brickley [mailto:Daniel.Brickley@bristol.ac.uk]
Sent: 05 May 1999 17:57
To: Makelainen, Milla [HAL02:HK00:EXCH]
Cc: 'www-rdf-comments@w3.org'
Subject: Re: "OR" in Schema spec



Hi

This is documented in 3.1.3 of the spec (below). Broadly, you need to
define the range of your property 'pet' to be some general class which
represents a superset of both cats and dogs. You might call this 'Pet'
(not different case convention).

eg.	pet -range-> Pet
	Cat -subClassOf->Pet
	Dog -subClassOf->Pet
	Poodle -subClassOf->Pet

Mammal might be a better example than "Pet" here but hopefully point is
clear. Excerpt from http://www.w3.org/TR/PR-rdf-schema/#constraints
follows...

cheers,

Dan

	although it is not possible to express two or more range constraints
on a
	property, a similar outcome can be achieved by defining a
        common superclass for any classes that represent appropriate
	values for some property. For example, to express the constraint
that a
        property xyz:drivesMotorVehicle can have values which are Vans,
	Trucks or PassengerVehicles, we assert that
        xyz:drivesMotorVehicle has a rdfs:range of MotorVehicle. If Van,
	Truck and PassengerVehicle are known to be
        sub-classes of MotorVehicle, then all these types of resource
	are acceptable values for xyz:drivesMotorVehicle. In cases where a
        common super-class does not exist, one can be defined in a
	schema in the normal manner. 


On Wed, 5 May 1999, Milla Makelainen wrote:

> Hi,
> 
> At the moment, it seems to be impossible to create an "OR" statement in
RDF
> schema. This is because a property can only have one "range" property and
> can therefore belong only to one class. How can I write a schema that says
> for example that "a pet can be either a cat or a dog" and then have a list
> of different breeds of cats and dogs in different classes?
> 
> Milla
> 
> Milla Makelainen
> Smart Network Technology, Nortel Networks
> email: millam@nortelnetworks.com
> tel. +44 (0) 1279 403270
> mobile +44 (0) 780 149 5538
> -- "Wisdom is being able to cope"
> 
> This message may contain information proprietary to Nortel Networks, so
any
> unauthorised disclosure, copying or distribution of its contents is
strictly
> prohibited.
> 
> 
Received on Thursday, 6 May 1999 05:40:10 GMT

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