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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
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