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Re: XML Schemas: Best Practices


> I may be on thin ice here but I don't think this is correct. If you use
> derivation using the above syntax you're not reordering the elements.
> you are extending the type to allow for all the elements in the base type

I believe you are right.  I think that Martin's intent was to use a
restriction element instead of an extension element (correct me if I am
wrong).  This would make his example:

     <complexType name="BookTypePlusReviewer">
             <restriction base="c:BookType" >
                     <element name="Reviewer" type="string"/>
                     <element name="Title" type="string"/>
                     <element name="Author" type="string"/>
                    <element name="Date" type="year"/>
                    <element name="ISBN" type="string"/>
                  <element name="Publisher" type="string"/>

I think this is a solid additional solution to the problem-- unfortunately I
don't what side I am on for "Best Practices".  It seems as though the size
of the restriction declaration would grow exponentially with each additional
restriction.  On the other hand (OTOH) utilizing the <any> element doesn't
give the same control.  For example in Roger's original message, using:

<any namespace="##any" minOccurs="0" maxOccurs="2"/>

at the top of the sequence seems to be a good idea until you consider
multiple layers of inheritance-- then you realize that a more extensive (no
pun intended) solution is needed.  So I guess this leaves me rooting for the
restriction and wishing there was another way.

Jeff Rafter
Defined Systems