XML Demystified

CHAPTER
4
XML Schema
As we discussed in Chapter 3, a parser is software you use to extract data from an
XML document. However, before it does this, the parser must learn about the XML
tags used to describe data in the document.
The parser has no way of knowing the XML tags unless you tell it what they are
by creating a document type definition (DTD), which you learned how to do in
Chapter 3. A DTD describes the structure of the XML document by defining XML
tags used in the document and relationships among these tags.
However, there is another way you can describe the structure of an XML
document: You can create an XML schema. An XML schema does everything a
DTD does and more, which is why many developers have switched to using it. In
this chapter, you’ll learn how to take advantage of an XML schema in your
application.
Copyright © 2005 by The McGraw-Hill Companies. Click here for terms of use.
51