Extra Complexity?

[Jeff Greif]

This seems a bit too thorough a rejection of DTD's for content validation.  It is helpful in
writing the application validation code for the prime number to be able to expect to have a
certain kind of element or attribute in a particular place that is the thing to be checked for
primality, and to know that a large subset of the other prerequisites needed for this kind of
check must have already been satisfied.  I find the parser's validation against a DTD valuable
in my application's code which is doing just this sort of thing.  It saves lots of checking
for various errors that cannot happen if the document is known to be valid according to the
DTD.

Jeff

"Samuel R. Blackburn" wrote:

> It depends on how you use XML. If you use it to transfer
> data between applications then DTD's are completely useless.
> Their assumption that the world is flat is inappropriate for
> data applications. Also, the validations performed using DTD's
> don't buy you anything. The application must perform its own
> validation based upon some business rules. DTD's allow you
> to "validate" that a field contains a number but you can't use
> DTD's to "validate" that a field contains a prime number (that
> is an application layer validation).
>


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