Beginning XML, 3rd Edition

by David Hunter, Andrew Watt, Jeff Rafter, Kurt Cagle, and John Duckett.

Table of Contents

1:What is XML?

2:Well-formed XML

3:Namespaces

4:DTD

5:Schemas

1. What is XML?

XML is a markup language, derived from SGML.

2. Well-formed XML

To be well-formed an XML document must satisfy several rules about its structure.

3. Namespaces

To help unambiguously identify the names of elements and attributes the notion of an XML namespace is used.

4. DTD

A document type definition, DTD, is a way to specify the permitted structure of an XML document.

5. Schemas

W3C XML Schema and Relax NG are two schema languages to specify the structure of XML documents.