Re: 'Schema Vs. XML' and 'Namespace Vs DTD'

Hi Arul,

This isn't really the appropriate list for your questions, as this
list is about XSLT, not schemas, namespaces or DTDs. A better list
would be XML-L (http://listserv.heanet.ie/xml-l.html), XML-Dev
(http://www.oasis-open.org/mlmanage/index.php) or xmlschema-dev
(http://lists.w3.org/).

> 1. I am having an XML file and its Schema. My clarification is how
> to validate my xml file against the schema. Is there any tool/engine
> exiting? Please advice.

I assume you're using W3C's XML Schema. If so, there's a selection of
validators and other tools at http://www.w3.org/XML/Schema#Tools. I
recommend using Xerces-J or MSXML to validate your document. You can
use Xerces-J easily using the <oXygen/> editor from
http://www.oxygenxml.com/ and you can use MSXML easily using
Topologi's Schematron Validator from http://www.topologi.com/.

> 2. What is namespace in xml? and How to implement this in DTD?
> Please explain me with example.

Namespaces are ways of defining families of elements and attributes so
that they can be distinguished from elements and attributes with the
same name but that have different meanings. For example, a namespace
allows you to distinguish between mathml:set (which defines a set in
mathematics) and svg:set (which sets a value during animation of a
graphic). A good overview of namespaces, with examples, by James Clark
is available at:

  http://www.jclark.com/xml/xmlns.htm
  
DTDs don't have proper support namespaces because they were designed
before namespaces existed. However, it's not hard to use namespaces
with DTDs if you are prepared to fix the prefixes that you use, and
there are hacks that you can use to incorporate namespaces with DTDs
even with flexible prefixes. The "Modularization of XHTML"
Recommendation at http://www.w3.org/TR/xhtml-modularization shows one
way to do this.

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/