Chapter 24. XML Path Language (XPath) Tad Tougher Tutorial
XPath applications
XPath data model
Location expressions
All XML processing depends upon the idea of addressing. In order to do something with data you must be able to locate it. To start with, you need to be able to actually find the XML document on the Web. Once you have it, you need to be able to find the information that you need within the document.
The Web has a uniform solution for the first part. The XML document is called a resource and Uniform Resource Identifiers are the Web's way of addressing resources. The most popular form of Uniform Resource Identifier is the ubiquitous Uniform Resource Locator (URL).
The standard way to locate information within an XML document is through a language known as the XML Path Language or XPath. XPath can be used to refer to textual data, elements, attributes and other information in an XML document.
As we have seen, both XSLT and XSDL make use of XPath for addressing.
