Re: XML Validity and DTD dependance

> I don't have a DTD yet want to constrain input to valid XML documents.
> Why can't I say "this is a valid XML document" without requiring everyone
> to have access to the DTD?  Why can't I uniqueness of ID be determined
> out of band, such as by schema?

If I understand you correctly, you seem to be equating validity with
uniqueness of IDs, which is only a small part of validity as the term
is normally used.

Is that right?  Are you in fact asking for a way to assert just
well-formedness plus uniqueness of IDs?

Just to be clear, here are the things which between them constitute
XML validity:

 - all elements, attributes, and notations must be declared
 - each element must be declared only once
 - the root element must have the correct name
 - the sequence of children must match the content model of parent
 - all required attributes must be present
 - attribute values must conform to their declared type
 - all entities must be declared (in some cases, this is part of
 - there must be at most one ID attribute per element
 - there must be at most one notation attribute per element
 - all ID values referred to be IDREF attributes must be defined
 - #FIXED attributes must have the declared value
 - ID values must be unique
 - "standalone" constraints must be met
 - all entities must be declared (in some cases, this is part of
   well-formedness)
 - logical and physical structure must be consistent (eg an element's start
   and end tags must be in the same entity)
 - various rules about the DTD itself must be met

-- Richard

Received on Friday, 22 April 2005 11:07:56 UTC