
Document Type Definitions (DTD) • 133
Standalone XML document
String attribute
System DTD
Tokenised attribute
Valid document
Well-formed document
CHAPTER SUMMARY
A Document Type Definition (DTD) allows us to validate the contents of an XML document.
A DTD is a plain text file, which may have an extension DTD. The XML and the DTD files are linked
through definition in the XML file. The use of DTD makes the processing of an XML document
faster at the application end, as they do not have to implement the logic of validating the XML.
The relationship between the XML document and the DTD is established by using the Document ...