was too speculative when it said that DCDs were intended to supersede
DTDs. We have a great quote from Tim Bray in InfoWorld
that "given the velocity and turmoil of events in this particular
industry and standards arena, anyone who ventured a strong answer either
way [whether DCDs will supplant DTDs] would have rocks in their head." :)
And yet, according to Microsoft, "DCDs will be necessary for any
developers looking to build three-tier Web applications using XML."
I guess we'll have to see how this plays out.
> Microsoft, IBM submit W3C proposal for XML data structure
> By Jeff Walsh, InfoWorld Electric
> Posted at 11:17 AM PT, Aug 18, 1998
> Microsoft and IBM recently submitted a proposal to the World Wide Web
> Consortium (W3C) for describing the structure and content of Extensible
> Markup Language (XML) data.
> The submission of Document Content Descriptions (DCDs) was acknowledged
> by the W3C, which will next form a working group to flesh out the
> DCDs provide similar functionality to Document Type Definitions (DTDs),
> which the XML world initially inherited from SGML, or Standard
> Generalized Markup Language. But DCDs extend further by supporting other
> XML-friendly standards such as Resource Description Framework (RDF),
> XML-Data and XML Namespaces.
> DCDs are also written in an XML syntax, unlike DTDs. This enables both a
> common markup language for both the DCD and the XML schema it
> represents, but also the same parser can be used for both the DCD and
> the XML data.
> According to Microsoft, DCDs will be necessary for any developers
> looking to build three-tier Web applications using XML.
> "There are some things you'll need that a DCD provides that a DTD does
> not," said David Wascha, product manager for platform marketing at
> Wascha noted that DCDs have support for database and programming-style
> prototypes. For example, in a DCD, a number can be designated an integer
> ('int' in programming talk) in the schema, which is not possible in a
> "You can call something an int and then send it to an equation, whereas
> DTDs allow you to do very generic description of a document," Wascha
> Neither Microsoft nor DCD co-author Tim Bray would say that DCD would
> supplant DTDs.
> "DCD is an alternative to DTD. It depends on what you're going to use it
> for," Wascha said.
> Bray, an independent consultant, said DCDs do provide a superset of the
> functions of DTDs, but it is too soon to announce the death of DTDs.
> "Given the velocity and turmoil of events in this particular industry
> and standards arena, anyone who ventured a strong answer either way to
> that question would have rocks in their head," Bray said.
My body has certainly wandered a good deal, but I have an uneasy
suspicion that my mind has not wandered enough.
-- Noel Coward