XML by Example

3

XML Schemas

In Chapter 2, “The XML Syntax,” you learned how to write and read XML

documents. More importantly, you learned that XML emphasizes the struc-

ture of documents.

This chapter further develops that theme by looking at the DTD, short for

Document Type Definition, a mechanism to describe the structure of docu-

ments. Specifically, you will learn how to

• model XML documents

• express the model in a DTD

• validate a document against its model

The DTD is the original modeling language or schema for XML. However,

for historical reasons, the DTD is somewhat limited and people are looking

for solutions to overcome these limitations. The W3C is working ...