Chapter 5: Understanding and Using DTDs

In This Chapter

Defining DTDs

Exploring what’s in an XML DTD

Understanding XML prolog

Declaring elements and their attributes

Declaring an entity

Noting notations

Knowing when and why to use a DTD

Including DTDs or definitions

Creating internal and external DTDs

Finding out what a document does to your DTD

What’s a DTD?
Reading a Simple DTD
XML Prolog
- XML declaration
- Document type declaration
- Comments
- Processing instructions
- What about that white space
Element Declarations
- Any or empty can do the trick
- Mixed content mixes it up
- Element content keeps your children in line
Attribute List Declarations
Entity Declarations
Notation Declarations
Deciding Whether to Have a DTD
Ways to Include DTDs or Definitions
- The inside view: Internal DTD subsets
- Calling for outside support: Referencing external DTDs
- Two is sometimes better than one
How Documents Digest DTDs