public function buildFieldReplacement(array $field_descriptor, $alias = false)
    {
        if ($alias === false) {
            $alias = $field_descriptor['name'];
        }

        switch ($field_descriptor['data_type']) {
            case 'int':
                $retval = "%d$alias\$d";
                break;
            case 'float':
            case 'double':
                $retval = "%F$alias\$d";
                break;
            case 'varchar':
            case 'text':
            case 'longtext':
            case 'enum':
            case 'set':
            case 'tinytext':
                $retval = "'%s$alias\$s'";
                break;
            default:
                $retval = false;
        }

        return $retval;
    }