[XML-SIG] XML Validation

Chris Herborth chrish at cryptocard.com
Tue May 18 15:34:30 EDT 2004

Jason Mobarak wrote:

> In short: what methods do you use to validate proper structure of an XML
> document?

I'm using pyRXPU to validate and parse the document into a DOM (using a 
pyRXPU -> DOM translator I wrote), along with a DTD.

> I'm definitely not an XML expert but from what I've heard my validation
>  solution is not part of the "real" XML tool chain -- the valid
> structure of my document is described by Python code. I should be able
> to have a schema or DTD that specifies structure and valid content.
> However, DTDs seem limited, I haven't seen that they can verify the kind
> of complex structure that I might want, am I wrong?

DTDs very accurately and fairly concisely describe the _structure_ of the 
document, schemas describe the possible _contents_ and most of the 
structure.  Yes, most of it, not all of it.

So, if you want to be 100% accurate in all cases, you need a DTD and an XSD.

It's been eight months since I used schemas for anything (previous job), so 
I can't remember exactly which bits of the structure the schema couldn't 
describe... oh, wait, maybe I can.  It was the content model for each tag. 
I don't think it could be properly expressed in the XSD.

Chris Herborth                                     chrish at cryptocard.com
Documentation Overlord, CRYPTOCard Corp.      http://www.cryptocard.com/
Never send a monster to do the work of an evil scientist.

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