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Re: DTD and Schema Teasers

• To: "'xml-dev@l...'" <xml-dev@l...>
• Subject: Re: DTD and Schema Teasers
• From: Rick Jelliffe <ricko@a...>
• Date: Thu, 18 Dec 2003 14:18:38 +1100
• In-reply-to: <15725CF6AFE2F34DB8A5B4770B7334EE03F9F08B@h...>
• References: <15725CF6AFE2F34DB8A5B4770B7334EE03F9F08B@h...>
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Bullard, Claude L (Len) wrote:

> 2.  What are good reasons for having multiple schemas for the same 
>    instance?
> 
>
* To model things by intersection.  For example, James Clark's XHTML 
schemas: one for
content models, one to model exclusion exceptions (e.g. that an <a> 
cannot contain another
<a> at any depth.)

* Often a schema may be company- or industry-wide, and be little more 
than a vocabulary
with a fairly open or variable content model. Particular uses of that 
vocabulary may have
their own restricted schemas. 

* When you have variants of some kind: validation in stages, an 
authoring schema compared
to a legacy-data schema, or even to document the effective schema that 
some application accepts
(which may not have complete coverage of all the elements in the 
notional schema.)

Cheers
Rick Jelliffe

• Follow-Ups:
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    • From: John Cowan <cowan@m...>

• References:
  • DTD and Schema Teasers
    • From: "Bullard, Claude L (Len)" <clbullar@i...>

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