XML Files with Linked External DTD Files

This section provides a tutorial example on how to store DTD statements in an external file, which can be then linked to XML files. The external DTD file should also have the 'xml' process instruction.

DTD File: A text file that contains DTD statements that define elements, attributes and entities of a document type for XML files.

Instead of including DTD statements inside an XML file, we can also store DTD statements in a DTD file, and link the DTD file to the XML file.

Here is a DTD file, hello.dtd, for my "hello.xml" file:

<?xml version="1.0"?>
<!ELEMENT p ANY>

Here is my "Hello world!" XML file linked to the external DTD file:

<?xml version="1.0"?>
<!DOCTYPE p SYSTEM "hello.dtd">
<p>Hello world!</p>

Note that:

Table of Contents

 About This Book

 Introduction of XML (eXtensible Markup Language)

 XML File Syntax

 XML File Browsers

 XML-JSON Document Conversion

 DOM (Document Object Model) Programming Interface

 SAX (Simple API for XML) Programming Interface

DTD (Document Type Definition) Introduction

 What Is DTD (Document Type Definition)

 XML Files with Embedded DTD Statements

XML Files with Linked External DTD Files

 Validating an XML File against a DTD Document Type

 Syntaxes of DTD Statements

 Validating an XML Document against the Specified DTD Document Type

 XSD (XML Schema Definition) Introduction

 Syntaxes of XSD Statements

 Validating XML Documents Against Specified XML Schemas

 XSL (Extensible Stylesheet Language) Introduction

 Java Implementation of XSLT

 XSLT (XSL Transformations) Introduction

 XPath (XML Path) Language

 XSLT Elements as Programming Statements

 Control and Generate XML Element in the Result

 PHP Extensions for XML Manipulation

 Processing XML with Python Scripts

 XML Notepad - XML Editor

 XML Tools Plugin for Notepad++

 XML Plugin Packages for Atom Editor

 XML 1.1 Changes and Parsing Examples

 Archived Tutorials

 References

 Full Version in PDF/EPUB