title: What is the need for an unsaved-value attribute in hibernate?
body: <p>What is the need for an <code>unsaved-value</code> attribute?</p>
  
  <pre><code>&lt;id name="userid" column="userid" type="java.lang.Long" unsaved-value="null"&gt;   
    &lt;generator class="sequence"&gt;
      &lt;param name="sequence"&gt;dmuseridseq&lt;/param&gt;
    &lt;/generator&gt; 
  &lt;/id&gt;
  </code></pre>