title: doctrine 2 , deleting row , contraint fails
body: <p>i tried deleting from a user  , inside the users entity, i have a one to many  property:</p>
  
  <pre><code>/** @OneToMany(targetEntity="\Entities\comments", mappedBy="comments", cascade={"persist"}) */
  protected $usercomments;
  </code></pre>
  
  <p>as there are comments, i cannot remove the main user... errors:</p>
  
  <blockquote>
    <p>SQLSTATE[23000]: Integrity constraint violation: 1451 Cannot delete or
    update a parent row: a foreign key constraint fails</p>
  </blockquote>
  
  <p>i also tried: cascade={"persist", "remove"}  , still no joy when deleting...  </p>
  
  <p>do i have to delete all comments for this user first in a loop then remove user as i thought it would delete all related automatically.</p>