标记相关对象以便销毁无效

Question

文档显示这是你如何标记和关联对象的破坏，但它不起作用。怎么会？

文档在http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html显示：

member.avatar_attributes = { :id => '2', :_destroy => '1' }
member.avatar.marked_for_destruction? # => true
member.save
member.reload.avatar # => nil

我有：

appointment.rb

class Appointment < ActiveRecord::Base
  belongs_to :time_block
end

time_block.rb

class TimeBlock < ActiveRecord::Base
  has_one :appointment
  accepts_nested_attributes_for :appointment, :allow_destroy => :true, 
                                              :reject_if => :all_blank

end

---

(rdb:144) @time_block.appointment_attributes = {"_destroy"=>"1", "id"=>"48"}

(rdb:144) p @time_block.appointment.marked_for_destruction?
false

Answer 1

如果您希望在销毁TimeBlock时销毁约会，请包括：

has_one :appointment, :dependent => :destroy

有关更多信息，请参阅：RailsGuides

Answer 2

mark_for_destruction仅在您将autosave: true添加到模型时才有效。

所以改变time_block.rb来使用：

has_one :appointment, autosave: 'true'

有关更多信息，请参阅https://apidock.com/rails/ActiveRecord/AutosaveAssociation/mark_for_destruction。

仅在为此关联模型启用父级上的：autosave选项时才有用。