title: how to do order-by in hibernate mapping
body: <p>suppose Object A has a list of Object B, and Object B must have a object C, B can be order base on C.level .</p>
  
  <p>In A.hbm.xml</p>
  
  <pre><code>&lt;bag name="listB"
               table="T_B"
               inverse="false"
               order-by="?? what should i do here???"
           &gt;
              &lt;key column="ID_A" not-null="true"/&gt;
              &lt;many-to-many column="ID_B" class="B"/&gt;
          &lt;/bag&gt;
  </code></pre>