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Re: Namespaces, W3C XML Schema (was Re: ANN: SAX FiltersforNamespaceProcessing)
- From: Ronald Bourret <firstname.lastname@example.org>
- To: Xml-Dev <email@example.com>
- Date: Tue, 21 Aug 2001 22:25:18 -0700
Elliotte Rusty Harold wrote:
> I am concerned that the theoretical use of schemas for typing is
> overriding their practical use for constraint checking.
The use isn't theoretical. Witness all the products that generate
classes from XML Schemas.
> Very few people
> are actually using schemas for typing. Instead they're being used for
I think it depends on how you do the counting. Clearly, the number of
people validating schemas outnumbers the number of people writing code
that explores them. This is a restatement of the fact that the number of
document authors is greater than the number of programmers.
If you count applications, validators are a minority.
> In validation, we need local types (if not necessarily unqualified
> local types) because the W3C XML Schema Language confuses the two
> separate issues of typing and constraints checking, especially when
> it comes to complex types. I don't want to see any prohibition on
> local types enshrined as a best practice, or otherwise deprecated.
Could you explain this further? Isn't constraints checking either (a)
the checking of data against types, or (b) the definition of domains for
a given type? (I suppose this also depends on what you mean by "type".)