This chapter provides a brief explanation of schemas and why they are important. It also discusses the basic schema design goals, and describes the various existing schema languages.
The word schema means a diagram, plan, or framework. In XML, it refers to a document that describes an XML document. Suppose you have the XML instance shown in Example 1–1. It consists of a
product element that has two children (
size) and an attribute (
Example 1–1. Product instance