NOTE: These slides have not been updated since 2003. They have been superseded by the book An Introduction to XML and Web Technologies Addison-Wesley, and the accompanying online material. Please see http://www.brics.dk/ixwt/ for more information. Anders Møller and Michael Schwartzbach, February 2006

THE XML REVOLUTION  -  TECHNOLOGIES FOR THE FUTURE WEB

XLink, XPointer, and XPath

Three layers:

• XLink
  • a generalization of the HTML link concept
  • higher abstraction level (intended for general XML - not just hypertext)
  • more expressive power (multiple destinations, special behaviors, linkbases, ...)
  • uses XPointer to locate resources

• XPointer
  • an extension of XPath suited for linking
  • specifies connection between XPath expressions and URIs

• XPath
  • a declarative language for locating nodes and fragments in XML trees
  • used in both XPointer (for addressing), XSL (for pattern matching), XML Schema (for uniqueness and scope descriptions), and XQuery (for selection and iteration)

These technologies are standardized but not all widely implemented yet.

XQuery vs. XPointer/XPath? Reminiscent, but different goals:

• XQuery: SQL-like database queries
• XPointer/XPath: robust addressing into known information

COPYRIGHT © 2000-2003 ANDERS MØLLER & MICHAEL I. SCHWARTZBACH