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ch08-dtd-validation
XML overview

Originally based on XML Visual Quickstart Guide by Kevin Howard Goldberg, and notes therefrom by Jack Davis (jcdavis@radford.edu).

Chapter 8 - Validation and Using DTD's

DTD's define rules for every element and attribute that can appear in an XML document. You must declare the DTD in an XML document in order to specify its use. Once this declaration is made, various tools can be used to validate the XML document against the DTD.

DTD's can be written and saved as separate files, or they can be written entirely within an XML document. Almost always, DTD's are specified in a separate file. Then the tag set they specify can be used to validate all the XML documents that refer to it.

• Creating and Using External DTD
  
  • Create the DTD in an external file.
  • In the XML document add a DOCTYPE declaration.
    
    <!DOCTYPE root SYSTEM "dtd.uri">
    "dtd.uri" is the URL of the DTD file
    
  • In the XML document change the XML declaration.
    <?xml version="1.0" standalone="no"?>
• Validating XML documents against a DTD
  
  • Make sure you include the declaration in the XML document.
  • Make sure the DTD file is publicly available (permissions).
  • Go to:
    http://validator.w3.org/
    Choose the method you want to use to handle the file. Then click check.
  • Be careful -- it takes some experience to properly decipher the error messages.

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©2011, Ian Barland, Radford University Last modified 2011.Mar.28 (Mon)

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