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Re: Default values for block and final

From: David Beech <David.Beech@oracle.com>
Date: Thu, 04 Jan 2001 11:58:57 -0800
Message-ID: <3A54D601.B8F6E3CD@oracle.com>
To: "Henry S. Thompson" <ht@cogsci.ed.ac.uk>
CC: "Arnold, Curt" <Curt.Arnold@hyprotech.com>, "'www-xml-schema-comments@w3.org'" <www-xml-schema-comments@w3.org>


"Henry S. Thompson" wrote:
> 
> "Arnold, Curt" <Curt.Arnold@hyprotech.com> writes:
> 
> > The Schema and DTD for Schema specify a default value of "" for block and final (but not in all uses) which will interfere with appropriate processing of blockDefault and finalDefault.  No default
> > should be provided so that not providing a block or final attribute can be distinguished from providing a value of "" which would indicate blocking nothing (anti #all)

There's an interesting analogy here with the use of xsi:null on an 
element in combination with minOccurs='0', since this also is needed
to distinguish between not providing anything, and providing an
"anti" value.

If the element is omitted, it is "not providing" any information
(e.g. that column value was not extracted from the database row).

If the element is present with xsi:null="true", it is "providing
a value" of the null attribute as "anti" normal element content
(e.g. that column value extracted from the database row had a null
value instead of a value of the specified type).

Thanks,

  David
Received on Thursday, 4 January 2001 15:02:28 GMT

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