Beginning XML Databases (Wrox Beginning Guides)

Overview

What is XPath? XPath is a specialized expression language used to parse through XML node hierarchies and retrieve chunks of data from XML documents. XPath is a major part of the scripting language eXtensible Style Sheet Transformations (XSLT). XSLT is a World Wide Web Consortium (W3C at http://www.w3.org) established standard along with other tools, such as XPointer and XQuery, both of which happen to be based on XPath. Therefore it is important to have a good understanding of XPath technology.

In this chapter you learn about:

• Building simple expressions using XPath

• Accessing inter-nodal relationships using XPath axes

• Using predicates to help filter XPath expression results

• Using wildcards in XPath expressions

• Retrieving multiple data sets using multiple XPath expressions

• Using built-in functions in advanced XPath expressions and XQuery