title: XSD complexContent restriction
body: <p>I found following example on <a href="https://www.w3schools.com/xml/schema_complex_empty.asp" rel="nofollow noreferrer">w3schools</a>.</p>
  
  <pre><code>&lt;xs:complexContent&gt;
    &lt;xs:restriction base="xs:integer"&gt;
      &lt;xs:attribute name="prodid" type="xs:positiveInteger"/&gt;
    &lt;/xs:restriction&gt;
  &lt;/xs:complexContent&gt;
  </code></pre>
  
  <p>I was searching through many documentations but still don't get it: When a complexContent has no "mixed" attribute the element does not have any text node and therefore does not need any data type. But why the <code>&lt;xs:restriction base="xs:integer"&gt;</code> ? As I understood this does absolutely nothing?</p>