- From: John Cowan <jcowan@reutershealth.com>
- Date: Fri, 22 Apr 2005 09:19:17 -0400
- To: Rich Salz <rsalz@datapower.com>
- Cc: Richard Tobin <richard@inf.ed.ac.uk>, "public-xml-core-wg@w3.org" <public-xml-core-wg@w3.org>
Rich Salz scripsit: > How about this? > I give you a document with[out] a DTD and say "it's valid XML." > > Why can't I do that? Why do I have to give you a DTD? XML validity is fundamentally different from validation against a W3C XML Schema or RELAX NG or Schematron schema. The purpose of schema validation of whatever flavor is to answer the question "Is the XML document consistent with the rules laid down in the schema document?" By contrast, XML validation answers the question "Is the XML document self-consistent?" Or to put it another way, "Do the elements and attributes in the document agree with the declarations in the same document?" A document "without a DTD" (that is, with neither an internal nor an external subset) doesn't contain any declarations, so it can't possibly be self-consistent in the relevant sense. (Note that I speak of XML documents, not XML entities; XML validation is determined for the entire document with all its entities, including the document entity, a possible external subset entity, possible external parameter entities, and possible external general entities.) -- There is / One art John Cowan <jcowan@reutershealth.com> No more / No less http://www.reutershealth.com To do / All things http://www.ccil.org/~cowan With art- / Lessness -- Piet Hein
Received on Friday, 22 April 2005 13:19:51 UTC