和before_save：before_update活动记录回调之间的区别是什么？ [英] What is the difference between the :before_save and :before_update Active Record callbacks?

问题描述

可能有人请向我解释之间的差异：before_save 和：before_update 在Ruby中的Active Record回调轨道4？

Could someone please explain to me the difference between the :before_save and :before_update Active Record callbacks in Ruby on Rails 4?

我通过活动记录回调官方文档阅读，但我无法找到一个颗粒状足够的解释。

I read through the official documentation on Active Record callbacks, but I couldn't find a granular-enough explanation.

推荐答案

：before_save 被称为每次一个记录插入/在数据库中更新。因此，它被称为每次保存是否其新记录或现有记录。

:before_save is called everytime a record is inserted/updated in the database. So it is called on every save whether its a new record or existing record.

：before_update 被称为只有当记录更新和放大器;从来没有上新的记录。

:before_update is called only when the record is updated & never on new record.

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