在 Rails 中销毁之前检查所有关联 [英] Check all associations before destroy in rails

问题描述

我的应用程序中有一个重要的模型，有很多关联.如果我想检查 before_destroy 回调中的所有引用，我必须执行以下操作:

I have an important model in my application, with many associations. If I want to check all the references in a before_destroy callback, i'd have to do something like:

has_many :models_1
has_many :models_2
mas_many :models_3
....
....
has_many :models_n

before_destroy :ensure_not_referenced

def :ensure_not_referenced
   if models_1.empty? and models_2.empty? and models_3.empty? and ... and models_n.empty?
       return true
   else
       return false
       errors.add(:base,'Error message')
   end
end

问题是，有没有办法一次执行所有验证?谢谢！

The question is, is there a way to perform all the validations at once? Thanx!

推荐答案

你可以通过 :dependent =>has_many 调用的 :restrict 选项:

You can pass the :dependent => :restrict option to your has_many calls:

has_many :models, :dependent => :restrict

这样，只有在没有其他关联对象引用它的情况下，您才能销毁该对象.

This way, you will only be able to destroy the object if no other associated objects reference it.

其他选项是:

• :destroy - 销毁所有调用其 destroy 方法的关联对象.
• :delete_all - 删除所有关联对象调用它们的 destroy 方法.
• :nullify - 将关联对象的外键设置为 NULL 无需调用它们的保存回调.

• :destroy - destroys every associated object calling their destroy method.
• :delete_all - deletes every associated object without calling their destroy method.
• :nullify - sets the foreign keys of the associated objects to NULL without calling their save callbacks.

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