title: Setting a nullable int to null
body: <p>In my Appraisal table I've got a field named "AppraisalTrace" which references to another table. This field is an int which can be null because I want to be able to create an Appraisal without an AppraisalTrace. I'm using an xsd to join Database and code.</p>
  
  <p>Now in my code when I'm creating an Appraisal I'm doing the following:</p>
  
  <pre><code>oAppraisalRow.SetAppraisalTraceNull();
  </code></pre>
  
  <p>this auto-generated method is provided by the dataRow but it's throwing the following exception when I try to insert an Appraisal with a Null AppraisalTrace:</p>
  
  <pre><code>Value for column "AppraisalTrace" in table "Appraisal" is DBNull
  </code></pre>
  
  <p>So how am I supposed to create my Appraisal?
  Thanks in advance!</p>