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From Brian Topping <topp...@codehaus.org>
Subject Re: DTD files
Date Mon, 21 Mar 2005 19:22:04 GMT
Hi Craig,

Yes, this is good.  I'll take a look at that.  From the conference call 
week back (sorry I missed everyone this week), we were considering that 
the public metadata specs ought to be in XSD, without DTD.  What do you 
think of that?  I'm not a big DTD user, so I don't know what the reasons 
are that people commonly want to use them.  The advantages of using XSD 
are that there is only one spec, that XSD is much more expressive, and 
it can be parsed with standard XML tools. 

If we are still going to maintain a DTD, I would suggest that it is a 
mistake to develop an XSD that is not a machine translation of the DTD, 
because no XSD is a better answer than an incorrect XSD resulting from 
not being maintained.  And if we are going to do a machine translation, 
I'd just suggest putting Trang into the build and make it a build-time 
artifact rather than checking it it.  It's a pretty slippery slope if we 
don't want to stay focused on XSD.

Another alternate is to use RelaxNG, which is reasonably expressive, can 
be written in XML (so it is can be parsed), and can be machine 
translated into both DTD and XSD.  It is not as expressive as XSD, but 
if I remember correctly, there are only a couple of XSD constructions 
that can't be done in it.  It does add the RelaxNG closure to the 
dependencies though.

Comments anyone?


Craig Russell wrote:

> Team,
> As I was checking in the dtd files for jdo2 (jdo.dtd and orm.dtd) I 
> had to think again about where we should put the official PUBLIC dtd 
> files. For JDO 1, it was clear that the site should be Sun. For JDO 2, 
> I believe that the answer still should be Sun, because the JCP 
> officially owns the IP to the dtd (and xml schema once we have that in 
> place).
> Does anyone think that we should change the official web location to 
> some other place like the Apache web site?
> Brian,
> The dtd files I checked in reflect the latest JDO specification draft. 
> I understand you're interested in converting these to .xsd. The last 
> time I saw an xsd for jdo was when Robin Roos made one for an earlier 
> draft. He might be able to help get you started with the task.
> Craig
> Craig Russell
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
> 408 276-5638 mailto:Craig.Russell@sun.com
> P.S. A good JDO? O, Gasp!

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