RE: How to store XML DTDs/Schemas on the web

Gavin Thomas Nicol (
Mon, 28 Jun 1999 04:28:01 -0400

> A "document type definition", "document definition" or DTD is a
> specification of a class of documents. Note that in SGML, a DTD is not
> the markup declarations (which is what commonly gets called the DTD) but
also any
> additional information necessary to characterise the document
> type.

Right the old "DTD vs DTD" trick (I remember this being a trick
question I was casually asked to see if I was "in the know" by
someone who shall remain nameless.).

> The notation of a vocabulary is quite useful, I think, when
> talking about namespaces in XML. XML namespaces are basically a means of
avoid name
> collisions in vocabularies. Namespaces solve the problem of combining
> vocabularies, not the problem of combining DTDs.

The problem I have with XML namespace is that it is really little more
than alpha renaming: kind of like the elisp idea of adding a package
prefix (Java kind of does the same thing).

The *real* problem is still one of matching ontologies. EDI/B2B is a
case in point, where the desire is not to reuse partial vocabularies
at all. XML namespaces do little here that could not have been accomplished
via other means (attributes etc).