public function updateOpAmount($opId)
 {
     $totAmount = 0;
     $chequesMapper = new Gyuser_Model_ChequesDataMapper();
     $chequesList = $chequesMapper->getApprovedCheckDetails($opId);
     foreach ($chequesList as $cheque) {
         $totAmount += $cheque->getAmount();
     }
     $data = array('amount' => $totAmount);
     $id = $this->getDbTable()->update($data, array('id = ?' => $opId));
     return $id;
 }