These fields are required for the flow to function correctly.

要使消息流正确运行，这些字段是必需的。

youdao

The fields created_on and updated_on are not required, but if you do include them, Rails maintains them automatically "behind the scenes"; in most cases there is no harm in using these timestamps.

域created _ on和updated _ on是不需要的，不过，如果您使用了它们，那么Rails会自动地“在后台”维护它们；在大部分情况下使用这些时间戳没有什么不好。

youdao