title: Primary and foreign keys in xml schema
body: <p>I am trying to insert primary and foreign keys in XSD schema file below :-</p>
  
  <p>Primary key is StudentID and Foreign Keys are courseID, AddressID, GradeID.</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
  &lt;xs:element name="Student"&gt;
    &lt;xs:complexType&gt;
      &lt;xs:sequence&gt;
        &lt;xs:element name="Title" type="xs:string"/&gt;
        &lt;xs:element name="FirstName" type="xs:string"/&gt;
        &lt;xs:element name="LastName" type="xs:string"/&gt;
        &lt;xs:element name="Dateborn"  type="xs:date"/&gt;
        &lt;xs:element name="Gender"  type="xs:string"/&gt;
      &lt;/xs:sequence&gt;
    &lt;/xs:complexType&gt;
  &lt;/xs:element&gt;
  &lt;/xs:schema&gt;
  </code></pre>
  
  <p>However above code is not working in my setup please help me in tracing the issue,</p>