Re: [xml-dev] DTD ID REF

From
Matt Gushee <>
To
Date
2002-07-18T14:05:26Z
ID
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Thread
Re: [xml-dev] DTD ID REF
On Thu, Jul 18, 2002 at 07:42:37AM -0600, Matt Gushee wrote:
> On Thu, Jul 18, 2002 at 09:22:32AM -0400, Yallala, Bhaskar wrote:
> > 
> > I have a DTD file in which I have element A which has two attributes with
> > IDREF properties. 
> > Now while creating xml file using DTD, how can I refer attribute IDREF
> > defined in another xml file?
> 
> You can't. That is a limitation of DTDs: IDs must be unique *within a
> given document*, and IDREFs must refer to an ID in the same document.
> If you want to enforce--hmm, I'm going to say "referential integrity,"
> borrowing from the database world--if you want to enforce that across
> separate documents, you need to do it in your application,

Hmm, I'm not sure that part was completely clear. What I mean is that in
order to accomplish what you want to do, you would need to define an
attribute of type CDATA or NMTOKEN--let's say it's called 'externalIDRef',
though it could be called whatever you want--and the application
processing your documents needs to understand that that attribute is
supposed to refer to an ID in another document.

-- 
Matt Gushee
Englewood, Colorado, USA

http://www.havenrock.com/