Question

我有一个模特：

class Merchant < ActiveRecord::Base
    belongs_to :billing_address, class_name: Address, dependent: :destroy
    belongs_to :other_address1, class_name: Address, dependent: :destroy
    belongs_to :other_address2, class_name: Address, dependent: :destroy
    belongs_to :other_address3, class_name: Address, dependent: :destroy
    belongs_to :other_address4, class_name: Address, dependent: :destroy
    ...
end

Address没有关联。

当我这样做时：

merchant.billing_address.destroy

在数据库中，地址记录消失了，但merchants.billing_address_id保留了虚假值。这是mysql，所以没有参照完整性。

我做错了什么？

注意：我意识到这可能更好地建模为has_one关联。我可能不得不去那里，但我不愿意。

更新：添加了一些代码来显示多个地址关联。

Answer 1

如果您希望在销毁帐单邮寄地址后Merchant.billing_address为空，则需要在地址模型中使用:dependent => :nullify。

参考http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html

Answer 2

事实证明，ActiveRecord不支持单侧belongs_to关联unlike other ORMs I've worked with。但你可以这样自己破解它：

before_save :remove_ids_for_nil_associations

def remove_ids_for_nil_associations
  self.billing_address_id = nil if is_getting_destroyed? self.billing_address
  ...
end

def is_getting_destroyed?(ref)
  ref.present? && ref.destroyed?
end

毁灭belongs_to离开FK

2 个答案: