protected function addColumn($name, $null, $default, $type, $size, $auto, $unsigned)
    {
        $this->columns[$name] = [
            'name' => $name,
            'null' => $null,
            'default' => $default,
            'type' => $type,
            'size' => $size,
            'auto' => $auto,
            'unsigned' => $unsigned
        ];
    }