|Lesson 10||A checklist for creating DTDs |
|Objective||Create a DTD from an existing set of tags. |
Checklist for creating Document Type Definitions
As you have seen so far, you can write well-formed XML by following a few simple rules.
In effect, these rules describe how to determine one of XML’s key characteristics: its structure.
Without the rules, the material is ambiguous and well-formedness only goes so far.
Several other technologies are available for validating XML documents, each with their own advantages and disadvantages.
Document Type Defi nitions (DTDs) offer a way of specifying further rules that help in the interpretation of documents and their structure.
By using namespaces it is possible to create unambiguously distinct sets of elements and attributes according the purpose you have in mind.
Whether or not they appear in a namespace, such special-purpose sets of terms are sometimes known as vocabularies.
You can describe the structure and vocabulary of a XML language in a software-friendly fashion, which can be used to check whether XML documents meet the requirements.
This checking is known as validation.
DTD Checklist - Exercise