public function isIdentity($column)
    {
        $this->_setupPrimaryKey();

        if (!isset($this->_metadata[$column])) {
            /**
             * @see Zend_Db_Table_Exception
             */
            // require_once 'Zend/Db/Table/Exception.php';

            throw new Zend_Db_Table_Exception('Column "' . $column . '" not found in table.');
        }

        return (bool) $this->_metadata[$column]['IDENTITY'];
    }