xml-dev - DTDs aren't going away even when schemas arrive (was Re: Are therestill

[Michael Champion <mike.champion@softwareag-usa.com>]

At 03:46 PM 7/31/00 -0700, yimin zhu wrote:
>I recently attended an XML training course and the instructor was teaching
>DTD rather than schema, so I asked him if there were still a lot of people
>using DTD rather than schema. I got a "yes", but I was not convinced. Does
>anyone have any idea?

Besides the reasons various people have already given, remember that there 
are certain things that you can do with DTDs, such as declare external 
entities, that I don't believe that you can do with any existing schema 
specs.  So whatever the future of schemas for declaring constraints on 
document structure and content, DTDs aren't going away in the forseeable 
future as the place to make such declarations.

And the question of how to handle the case where both the DTD and schema 
contain content model constraints is not easy to answer.  I write this 
[sorry, Lauren!] while listening to the DOM WG beat their collective heads 
against the wall trying to figure this out ... and lets not even talk about 
the little nuggets of complexity that namespaces throw into this toxic stew.