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Re: Does RDF overlap w/XML Schema

From: Tom Van Eetvelde <tom.van_eetvelde@alcatel.be>
Date: Thu, 16 Nov 2000 10:18:20 +0100
Message-ID: <3A13A65C.945DA498@alcatel.be>
To: Renato Iannella <renato@iprsystems.com>
CC: www-rdf-interest@w3.org
Renato Iannella wrote:

> [...]
>
> RDF 2.0 should be completely expressable with XML Schema.
> (The web can only handle one schema language)
>
> Until this happens, RDF will always be the "poorer cousin" to XML
> Schema.

Hello Renato,

I disaggree with this. I'll give a practical example where XML Schema and RDF essentially differ
from each other.

RDF schema provides 'XML' tags to represent resources. Each resource has the right to exist on its
own in an RDF instance (XML serialized) document. This means that you can start the document with
any tag from your schema.

XML schema tells you how tags are nested. However, only some tags may appear as first tag of a XML
document instance. This is essentially the difference in practice (for people coming from an XML
world)!

Suppose you have the following model in mind: a person has a name consisting out of a first name,
last name and a nickname.

This gives the XML tags: <Person>, <Name>, <FirstName>, <LastName>, <NickName>. With your XML
schema, you have to define how these tags can be nested and what may be the roottags. If you want
several roottags to be possible, you need to construct several XML Schema's.

In an RDF schema, you need to define the relationship between these tags, but more importantly, once
you have your schema (only 1), you can start your document with any tag and add tags in any order.
Tags don't even have to be nested as each resource has an ID to which you can refer.

I hope this helps. I tried to write it for people with an XML background, trying to leave out as
much as possible RDF terminoligy.

Greetings,

Tom.

Received on Thursday, 16 November 2000 04:21:20 GMT

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