ruby-on-rails - rails 3 : rollback for after_create

Question

我有一张报名表。

当用户注册时，应用程序应该将数据保存在 enrollments 表和 users 表中。 (我需要这种分离，因为用户的个人资料可以更改，但他为该特定注册输入的数据必须存档。因此，即使以后用户更改了他的姓氏，在注册表格中我也会有他的初始信息。)

所以我正在考虑将数据保存在 enrollments 表中，然后进行 after_create 调用，就像这样...

class Enrollment < ActiveRecord::Base

  after_create :save_corresponding_user

  def save_corresponding_user
    user = User.new
    user.full_name = self.user_full_name
    user.email = self.user_email
    user.mobile_phone = self.user_mobile_phone
    user.save
  end
end

问题是，如果由于任何原因保存用户失败怎么办。如何回滚并销毁 enrollments 表中刚刚保存的数据？

Answer 1

从 after_create 返回 false 将不执行任何操作。

The whole callback chain is wrapped in a transaction. If any before callback method returns exactly false or raises an exception, the execution chain gets halted and a ROLLBACK is issued; after callbacks can only accomplish that by raising an exception.

此外，您必须引发 ActiveRecord::Rollback:

Any exception that is not ActiveRecord::Rollback will be re-raised by Rails after the callback chain is halted. Raising an exception other than ActiveRecord::Rollback may break code that does not expect methods like save and update_attributes (which normally try to return true or false) to raise an exception.

http://guides.rubyonrails.org/active_record_callbacks.html#halting-execution

我做这样的事情:

after_create do
  if condition
    errors.add(:attr, 'Blah blah blah.')
    raise ActiveRecord::Rollback
  end
end

对于 Rails 3:http://guides.rubyonrails.org/v3.2.13/active_record_validations_callbacks.html#halting-execution