title: xml schema validation error "prefix is not bound"
body: <p>I am entirely new to XML Schema and am trying to get the basics down. Here is my xml schema code (filename: example1.xsd):</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
  xmlns:sample="http://www.example" 
  targetNamespace="http://www.example.com" 
  elementFormDefault="qualified"&gt;
  
  &lt;xs:element name="school"&gt;
    &lt;xs:complexType&gt;
      &lt;xs:sequence&gt;
        &lt;xs:element name="element1" type="xs:string"/&gt;
        &lt;xs:element name="element2" type="xs:string"/&gt;
        &lt;xs:element name="element3" type="xs:string"/&gt;
        &lt;xs:element name="element4" type="xs:string"/&gt;
      &lt;/xs:sequence&gt;
    &lt;/xs:complexType&gt;
  &lt;/xs:element&gt;
  
  &lt;/xs:schema&gt; 
  </code></pre>
  
  <p>Here is the XML document.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  
  &lt;sample:school xmlns="http://www.example.com"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="./example1.xsd"&gt;
  
        &lt;element1&gt;hello&lt;/element1&gt;
        &lt;element2&gt;hello&lt;/element2&gt;
        &lt;element3&gt;hello&lt;/element3&gt;
        &lt;element4&gt;hello&lt;/element4&gt;
  
  &lt;/sample:school&gt;
  </code></pre>
  
  <p>Upon trying to validate the xml file, I get an error from netbeans that says:
  The prefix "sample" for element "sample:school" is not bound. [9] </p>