Ruby on Rails:updated_at - 在创建时设置为 0 [英] Ruby on Rails: updated_at - set as 0 on creation

问题描述

当我在 query 表上创建新记录时，我希望 updated_at(时间戳)为 '0000-00-00 00:00:00' - 而不是当前时间戳，Ruby on Rails 默认设置.

When I create a new record on query table, I want updated_at (timestamp) to be '0000-00-00 00:00:00' - and not the current timestamp, as Ruby on Rails sets by default.

MySQL 字段:

`updated_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP

然而，Ruby on Rails 生成了这个 sql 查询:

However, Ruby on Rails generates this sql query:

INSERT INTO `queries` (`updated_at`) VALUES ('2011-01-04 17:40:15')

我该如何解决这个问题?

How do I fix this?

推荐答案

Rails 将 updated_at 设置为当前时间，因为这是最近更新记录的时间.它将更新视为一种创造.如果您想检查某些内容是否曾经更新过，请检查其 updated_at 和 created_at 是否相同.

Rails sets updated_at to the current time because, well, thats when the record was most recently updated. It sees an update as a creation. If you want to check if something has ever been updated, check to see if its updated_at and created_at are the same.

否则，您应该能够通过在插入时强制属性来更改插入的值.

Otherwise, you should be able to change the value inserted by forcing the attribute upon insertion.

Post.new(@params.merge({:updated_at => DateTime::new})

或者，在模型的 before_create 方法中，设置 self.updated_at = DateTime::new.

or, in a before_create method on your model, set self.updated_at = DateTime::new.

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