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Hello!

I'm looking for a method or tool to transcribe a XML-Schema (more
precisely the W3C XML-Schema Schema) to a classic DTD. That
is, I have a xyz.xsd file and want to have a xyz.dtd file. Not the
other way round.

The effect should be that any file which is valid according to
the XML-Schema is also valid according to the generated DTD.

I'm aware of the fact that for instance namespaces and such
constructs will introduce some complexity, but in the end
XML-Schema contains more constraints than the DTD formalism,
therefore -- from a theoretical point of view -- it should be
feasible. But has it already be done?

No search engine or FAQ-file I found on the net contained a
usable pointer, preventing me to reinvent the wheel. But maybe
the experts on this lists may have a hint.

Any help appreciated!

--
Martin Froehlich
System Development
Telefonica Deutschland GmbH

Martin Froehlich wrote:

> Hello!
>
> I'm looking for a method or tool to transcribe a XML-Schema (more
> precisely the W3C XML-Schema Schema) to a classic DTD. That
> is, I have a xyz.xsd file and want to have a xyz.dtd file. Not the
> other way round.
Martin,

I know that the (IBM product) WebSphere Studio Application Developer
can do this. It costs $$$. Since it is based on Eclipse, there exists
the slim possibility that Eclipse itself can do this, and Eclipse is
freely downloadable.

Regards,
Kenneth

Martin Froehlich wrote:

> Hello!
>
> I'm looking for a method or tool to transcribe a XML-Schema (more
> precisely the W3C XML-Schema Schema) to a classic DTD. That
> is, I have a xyz.xsd file and want to have a xyz.dtd file. Not the
> other way round.

Most of the big DTD/Schema design tools can do this, eg XML Spy.
But you risk losing some constraints.

> The effect should be that any file which is valid according to
> the XML-Schema is also valid according to the generated DTD.

Not possible to guarantee this.

> I'm aware of the fact that for instance namespaces and such
> constructs will introduce some complexity, but in the end
> XML-Schema contains more constraints than the DTD formalism,
> therefore -- from a theoretical point of view -- it should be
> feasible. But has it already be done?

No, the opposite is true: W3C Schema allows you to specify constraints
which cannot be specified in a DTD, so converting a W3C Schema to a
DTD means you may have to forego those constraints which cannot be
represented in a DTD.

///Peter
--
"The cat in the box is both a wave and a particle"
-- Terry Pratchett, introducing quantum physics in _The Authentic Cat_