Re: Why Are Schemas Hard?

[Joe English <jenglish@flightlab.com>]

I just wrote:

> When I figured out that the sample XSD fragment
>
> | <complexType name="myNewNameType">
> |	[ ... ]
> | </complexType>
> | <element name="employee" type="dc:myNewNameType" />
>
> means, basically,
>
>     <!ELEMENT employee 	(name, location) >
>     [...]


Of course the XSD version and the DTD version don't
*really* mean the same thing; the XSD version defines
several things that the DTD can't even express
(a new type "myNewNameType" which can be subclassed and
reused, locally-scoped type bindings for the generic
identifiers 'name' and 'location', etc.)

It's just that most of the time I don't need any of the
extra things that XSD can express; usually I just need
to say

     <!ELEMENT employee (name, location) >

XSD makes explicit a lot of what's implicit in the DTD syntax.
On the one hand, this lets you override, name, and reuse
these entities; on the other hand, it makes you spell them
out.  (The shorthand versions can save some typing, but the concepts
are still there, implicitly explicit.)


--Joe English

  jenglish@flightlab.com