public function getMetaColumns($tableName){
        $stmt = $this->query(self::META_COLUMNS_SQL, array($tableName));
        if ($stmt === false){
            return array();
        }

        $rows = array();
        foreach ($stmt as $row){
            switch($row[1]){
            case 'float8':
            case 'numeric':
                $type = PDO::PARAM_STR; // Not exists PARAM_FLOAT by current version.
                break;

            case 'int4':
            case 'int8':
                $type = PDO::PARAM_INT;
                break;

            case 'bool':
                $type = PDO::PARAM_BOOL;
                break;

            default:
                $type = PDO::PARAM_STR;
                break;
            }

            $rows[$row[0]] = $type;
        }

        return $rows;
    }