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Re: A valuable lesson on the difference between XML Schemas and ontologies

From: Eliot Kimber <ekimber@reallysi.com>
Date: Fri, 4 Nov 2011 09:29:49 -0500
To: "Costello, Roger L." <costello@mitre.org>, "xmlschema-dev@w3.org" <xmlschema-dev@w3.org>
Message-ID: <CAD9610D.20F06%ekimber@reallysi.com>
XML schemas are nothing more than document syntax constraint specifications.
There is no sense in which then can be anything more than a very weak
reflection of some deeper ontology that governs the semantic objects for
which the XML governed by the XSD schema is one possible serialization.

That is, ontologies describe relationships among things, schemas define
syntactic constraints on XML elements. The fact that the XSD mechanism has a
weak facility for defining type hierarchies does not make it a language for
describing taxonomies or ontologies.

The map is not the territory.



On 11/4/11 9:19 AM, "Costello, Roger L." <costello@mitre.org> wrote:

> Hi Folks,
> This week I learned a valuable lesson on the difference between XML Schemas
> and ontologies. I think you will find it of interest.
> Warning: in the following two sections I will lead you down a path and attempt
> to persuade you that everything is reasonable and logical. Then, in the two
> sections after that I will change my position 180 degrees and attempt to
> persuade you that what I said previously is unreasonable and illogical.
> ------------------------------------------------------------------------------
> ---------
> The Problem: Element Has No Information About The Kind Of Thing It Is
> ------------------------------------------------------------------------------
> ---------
> In this section and the next I will attempt to persuade you to connect every
> element in your XML Schema to a semantic identifier.
> ---
> Some XML Schemas declare elements and do not associate them to anything. That
> is, there is no indication of what kind of thing an element is. For example,
> in the following XML Schema there is no indication of what kind of thing the
> title element is:
>       <element name="title" type="string" />
> That element declaration states the name of the thing (title), the type of
> data that the thing can have (string), but it says nothing about what kind of
> thing it is.
> More ... http://www.xfront.com/What-Kind-Of-Thing-Is-It.pdf
> Comments welcome.
> /Roger

Eliot Kimber
Senior Solutions Architect
"Bringing Strategy, Content, and Technology Together"
Main: 512.554.9368
Received on Friday, 4 November 2011 14:37:11 UTC

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