XML Review

In this tutorial, we have established the following:

  • XML is a markup language
  • XML uses elements as basic structural components; elements are defined by an opening tag and a closing tag, between which content is sandwiched:
  • Markup language elements can close themselves:
    <tag />
  • Elements can be nested within each other, much like folders on a computer:
    <tag3 />
  • Unless otherwise specified, nested elements take on the characteristics of elements within which they are nested
  • Markup language documents typically begin with a root element within which all other elements are nested
  • Markup language elements can be modified by attributes; there can be multiple attributes per tag and multiple values per attribute:
    <tag attribute="value" />
  • Markup language elements can be differentiated from one another by namespaces, which identify a specific context in which a given element should be interpreted
  • Namespaces must be declared using the xmlns attribute
  • Prefixes refer to and invoke a namespace to which the prefix has been bound; this binding must take place within a given element or within an element that acts as a parent to the element in which the prefix is used
  • Prefixes can modify tags, attributes, and content:
    <prefix:tag prefix:attribute="value">prefix:content</prefix:tag>

With this background, it should now be possible to understand and interact with USGIN XML documents more easily.

This concludes the USGIN XML Tutorial.