<?php
switch($conn->getState())
    case Doctrine_Connection::STATE_ACTIVE:
        // connection open and zero open transactions
    break;
    case Doctrine_Connection::STATE_ACTIVE:
        // one open transaction
    break;
    case Doctrine_Connection::STATE_BUSY:
        // multiple open transactions
    break;
    case Doctrine_Connection::STATE_CLOSED:
        // connection closed
    break;
endswitch;
?>