• XMLRevision

MSc Revision Notes - XML

Exam topics

Main topics

• XML overview
• DTDs
• Schema
• XPath
• XSL

Notes

• XML syntax rules:
  • Case sensitive
  • Element/attribute names beginning with 'xml' are reserved.
  • Root element is required
  • End tags are required
  • Elements must be properly nested
  • Attribute values must be enclosed in quotes
  • Entity references must be declared

• If a document observes the syntax rules of XML it is well-formed

• A valid document is well formed and has been validated against a DTD.

• 5 built-in entities:

  & (&)
  &lt; (<)
  &gt; (>)
  &quot (")
  &apos; (')
  

• Everything inside a CDATA section is ignored by the parser. <![CDATA[this is not parsed]]>

Elements vs attributes

• Elements
  • Elements may be nested.
  • Order is always present
• Attributes
  • Attributes can only be simple values
  • No ordering implied
  • Name cannot repeat
  • Tend to be used to provide more information about an element
  • Special features when used with DTDs

DTDs

• DTDs define the XML document structure with a list of legal elements.

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