yii\db\ColumnSchemaBuilder::__toString PHP Method

    public function __toString()
    {
        switch ($this->getTypeCategory()) {
            case self::CATEGORY_PK:
                $format = '{type}{check}{comment}{append}';
                break;
            default:
                $format = '{type}{length}{notnull}{unique}{default}{check}{comment}{append}';
        }
        return $this->buildCompleteString($format);
    }