XSLT, XML Schema, and XPath

XSLT, XML Schema, and XPath Matt McClelland

Introduction • XML Schema • Defines the content and structure of XML data. • XSLT • Used to transform XML documents into other XML documents or text-based formats such as HTML and PDF. • XPath • Used as a way to locate and tag “items” or nodes in an XML document.

XML Schema • What is an XML Schema? • XML Schema documents are used to define and validate the content and structure of XML Data. • Primarily used to separate content from formatting

XML Schema (cont.) • Follows Strict Hierarchical Structure • Every well-formed XML Schema document (.xsd) follows a tree-like structure • Contains root, child, and leaf nodes/tags • Restricts documents to a fixed vocabulary and validates documents to ensure they follow the rules of the dialect • Contains only Structural/Semantic Data • XML Documents contain NO formatting information..

XSLT • What is XSLT? • XSLT stands for eXtensible Stylesheet Language Transformations. • Used in conjunction with XSL Stylesheets and XPath to render and style XML and other text-based documents.

XSLT (cont.) Advantages Disadvantages • Clean, concise templates • Relatively fast • Provides an easy, platform neutral way to render XML into HTML, PDF, and other XML docs • Stylesheets may become difficult to maintain, especially if left unkempt • Not easily readable or understandable at a glance • Not supported by all web crawlers or older internet browsers

XPath • What is XPath? • XPath is a query language often used in conjunction with XSLT for selecting nodes from an XML document. • Addresses ‘parts’ of an XML document and provides basic facilities for computing and manipulating strings, numbers, and booleans from the content of an XML document.

XPath (cont.) • How does it work? • XPath uses a compact, string-based, rather than XML element-based syntax. • Operates on the abstract, logical structure of an XML document (tree of nodes) rather than its surface syntax. • Uses a path notation (much like URLs) to navigate through the XML’s hierarchical tree structure.

SpecifyXSL Stylesheet Sample XML

XSL version XPath XSLT Example classical.xsl <xsl:stylesheetxmlns:xsl="http://www.w3.org/TR/WD-xsl"> <xsl:template match="/"> <HTML> <HEAD><TITLE>Authors</TITLE></HEAD> <BODY> <H1>Composers from Austria</H1> <TABLE BORDER="1"><TR><TH>Name</TH></TR> <xsl:for-each select="/authors/author[nationality='Austrian']"> <TR><TD><xsl:value-ofselect="name" /></TD></TR> </xsl:for-each> </TABLE> </BODY> </HTML> </xsl:template> </xsl:stylesheet>

Output Original XML Transformed XML

Questions?

XSLT, XML Schema, and XPath