protected function _quoteInsert($query)
    {
        list($table, $columns) = $query->clause('insert');
        $table = $this->_driver->quoteIdentifier($table);
        foreach ($columns as &$column) {
            if (is_scalar($column)) {
                $column = $this->_driver->quoteIdentifier($column);
            }
        }
        $query->insert($columns)->into($table);
    }