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Re: Options for dealing with IDs

From: Rick Jelliffe <ricko@topologi.com>
Date: Wed, 22 Jan 2003 23:39:29 +1100
Message-ID: <08ee01c2c213$4ffb9490$4bc8a8c0@AlletteSystems.com>
To: <www-tag@w3.org>

 Steven Pemberton wrote:

> Can anyone explain to me what breaks when an element has two (different)
> names? Why does XML prevent you from having more than one attribute of type
> ID on an element?

Because there are no constraints that partitition IDREFs to point to IDs on particular
elements, there are no links that can be created by having multiple IDs-pre-element
that  cannot also be created by single IDs-per element. From that POV, 
multiple IDs are a syntactical sugar, and one of the few times SGML does not
go overboard. 

So multiple IDs per element are no required because of modeling, but 
to allow composition of schemas from multiple attribute lists (at the moment
you cannot arbitrarily combine two attribute lists, in case both have IDs).

Rick Jelliffe
Received on Wednesday, 22 January 2003 07:37:43 UTC

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