Re: XML Schemas: Best Practices

[Martin Bryan <mtbryan@sgml.u-net.com>]

Len identified a number of possible reasons for wanting to use abstract
typing of elements. Let me add another one that is specific to W3C Schemas.
In business applications you often need to use a commonly understood
element, but the rules that you want to apply to the validation of its
content change according to the context in which the element is being
applied. For example, one company may number all its products, while another
may name them all. Now that datatypes are available as part of the
specification of the validation process you might need to be able to change
the datatyping rules without changing the actual model of the element, or
its attributes.

Martin Bryan