XML Schema

Chapter 2. Our First Schema

Starting with a simple example (a limited number of elements and attributes and containing no namespaces), we will see how a first schema can be simply derived from the document structure, using a catalog of the elements in a document as we write a DTD for this document.

The Instance Document

The instance document, which we use in the first part of this book, is a simple library file describing a book, its author, and its characters:

<?xml version="1.0"?> 
<library>
  <book id="b0836217462" available="true">
    <isbn>
      0836217462
    </isbn>
    <title lang="en">
      Being a Dog Is a Full-Time Job
    </title>
    <author id="CMS">
      <name>
        Charles M Schulz
      </name>
      <born>
        1922-11-26
      </born>
      <dead>
        2000-02-12
      </dead>
    </author>
    <character id="PP">
      <name>
        Peppermint Patty
      </name>
      <born>
        1966-08-22
      </born>
      <qualification>
        bold, brash and tomboyish
      </qualification>
    </character>
    <character id="Snoopy">
      <name>
        Snoopy
      </name>
      <born>
        1950-10-04
      </born>
      <qualification>
        extroverted beagle
      </qualification>
    </character>
    <character id="Schroeder">
      <name>
        Schroeder
      </name>
      <born>
        1951-05-30
      </born>
      <qualification>
        brought classical music to the Peanuts strip
      </qualification>
    </character>
    <character id="Lucy">
      <name>
        Lucy
      </name>
      <born>
        1952-03-03
      </born>
      <qualification>
        bossy, crabby and selfish
      </qualification>
    </character>
  </book>
</library>

Our First Schema

We will see, in the course of this book, that there are many different styles for writing a schema, and there are even more approaches to deriving ...