Re: Included <schema>
Jean-Jacques Thomasson <[email protected]> Wed, 27 Feb 2013 20:26:16 +0100
| Newsgroups | gmane.text.xml.schema.devel |
|---|---|
| Message-ID | <[email protected]> |
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Thanks George<br>
<br>
I join late this interesting discussion you initiated after our
discussion on the problem of the *big* model S1000D+DITA.<br>
The presentation of that problem may give new inputs/thoughts to the
discussion.<br>
<br>
The case is a model (schema) defining 1850 elements and 650
attributes.<br>
Such a big schema must be designed in a way that makes its writing
and maintenance clear and simple.<br>
It must also be designed in a way that eases the testing and makes
simple the management of the change of components.<br>
For the interconnection of S1000D and DITA, the result is a set of
148 schemas, all linked together.<br>
A UML representation of this big model has been done : It was the
only way to design, define, verify and manage correctly the logic of
all the <xs:include>, <xs:redefine> and
<xs:import> used in those schemas.<br>
<ul>
<li>One challenge was to have each included or imported schema
being valid on its own : As Michael Kay has written, we think
that it is not humanely acceptable to manage big schemas where
included schemas are "partially valid" or "valid only when they
are included in including schema" or "valid when used with some
instances and invalid for the others". Checking the global
validity would be a mess and be probably just impossible to
realize.<br>
</li>
<li>Since S1000D is <u>the</u> standard for many industries (the
entire Aerospace & Defence industries worldwide), it is not
possible to propose schemas to this industry which would not be
perfectly valid, with no doubt. It is an obligation that the
normative committee of S1000D can declare those schemas valid <u>independently
from any context</u>. This will be even more true if we
propose a big S1000D+DITA model to the industry.<br>
</li>
<li>EPWG (S1000D Electronic Publications working Group) must be
able to test each component of the S1000D model.</li>
<li>Flexibility is mandatory and we found that managing libraries
of components was the best for that. A group of industries, for
the purpose of one project, should easily write a new sub
version of the original schema(s).</li>
<li>Handling recursive inclusions is inevitable and should not be
a problem to a parser.</li>
</ul>
For those interested by this big model, I will provide it on demand.<br>
<br>
Regards<br>
Jean-Jacques<br>
<br>
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