Ruby on Rails的：为什么ActiveRecord的使用＆QUOT;日期时间＆QUOT;类型而不是＆QUOT;时间戳＆QUOT;时间戳字段？ [英] Ruby on Rails: why ActiveRecord uses "datetime" type instead of "timestamp" for timestamp fields?

问题描述

在我的数据库迁移文件，我插入的行：

In my database migration file I inserted the line:

t.timestamps

两列，如我所料，创建的updated_at和created_at。然而，他们的类型是日期时间，而不是时间戳。

Two columns, as I expected, were created: "updated_at" and "created_at". However, their type is "datetime" and not "timestamp".

我使用MySQL和时间戳型，据我所知，的设计正是为了这样的情况下，因为它使用较少的空间，是独立的时区。

I am using MySQL and the "timestamp" type, as I understand, is designed exactly for such cases, as it uses less space and is independent of timezone.

那么，有没有任何理由，为什么Rails 3中使用日期时间，而不是时间戳？我应该尝试解决这个问题？如果是的话，有没有办法，除了不使用t.timestamps每一次分别定义的updated_at和created_at栏目为每个新表来做到这一点？

So, is there any reason, why Rails 3 uses "datetime" and not "timestamp"? Should I try to fix that? If yes, is there any way to do this besides not using "t.timestamps" and defining "updated_at" and "created_at" columns separately every time for each new table?

推荐答案

从内存中，MySQL的时间戳列类型的行为类似于的updated_at 的，因为它与每当记录被更新为当前时间更新。

From memory, the mysql timestamp column type behaves similar to updated_at in that it is updated with the current time whenever the record is updated.

虽然这是针对的updated_at 列有用的，这不是 created_at 所需的行为。

While this is useful for the updated_at column, this is not the desired behaviour for created_at.

此外，Rails的处理在你的应用程序的设置规定（应该通常被设定为UTC），因此使用MySQL的时间可能与其他日期时间记录不一致时区。

In addition, Rails handles the timezone as specified in your app's settings (should would normally be set to UTC), so using mysql's time may be inconsistent with other datetime records.

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