Chapter 8. Constraining XML with Schemas

Reading, writing, manipulating, navigating, and transforming an XML document is all well and good if you know what the document is supposed to look like. That's likely to be the case if you're developing tools in-house to deal with data formats that you control; but if you want to interchange XML data with other systems, you would probably find it convenient to define a more rigid structure for your documents.

You're not the only one to think of that, of course. Although the original XML specification included Document Type Definitions as an optional mechanism for defining a document's structure, developers quickly outgrew DTD's fairly limited capabilities. The World Wide Web Consortium developed W3C XML Schema to provide a mechanism for creating more formalized structure for XML documents. XML Schema was formally adopted as a W3C recommendation in 2001.

In this chapter, you'll learn about W3C XML Schema, and how .NET implements it. You'll see how to create XML Schemas using the .NET XML Schemas/DataTypes support utility. You'll work with schemas through both the standard XML types and the System.Xml.Schema assembly. And you'll look at some examples of data interchange, using XML Schema to constrain and validate XML data.