Ruby on Rails 回调，:before_save 和:before_create 之间有什么区别? [英] Ruby on Rails Callback, what is difference between :before_save and :before_create?

问题描述

您能否详细解释一下 :before_save 和 :before_create Ruby on Rails 回调是什么，以及它们与 Rails 验证有什么关系?:before_save 或 :before_create 之后是否进行验证?

Could you explain in detail what the :before_save and :before_create Ruby on Rails callbacks are, and what they have to do with Rails validations? Does validation occur after :before_save or :before_create?

推荐答案

在 Rails 下的 create 操作中，数据库操作前有六个回调，后有两个.按顺序，这些是:

In a create operation under Rails, there are six callbacks before the database operation, and two after. In order, these are:

1. before_validation
2. before_validation_on_create
3. after_validation
4. after_validation_on_create
5. before_save
6. before_create
   
   数据库插入
7. after_create
8. after_save

更新操作具有完全相同的设置，除了在任何地方读取 update 而不是 create(以及 UPDATE 而不是 INSERT).

Update operations have exactly the same set, except read update instead of create everywhere (and UPDATE instead of INSERT).

由此，您可以看到验证是在 before_save 和 before_create 回调之前执行的.

From this, you can see that validation is carried out before the before_save and before_create callbacks.

before_save 出现在 before_create 之前.据我所知，他们之间什么也没有发生.但是 before_save 也会在更新操作时触发，而 before_create 只会在创建时触发.

The before_save occurs slightly before the before_create. To the best of my knowledge, nothing happens between them; but before_save will also fire on Update operations, while before_create will only fire on Creates.

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