如何自动删除Rails应用程序中的孤立实体

Question

我使用的是Rails 4.2.7。当我不再有对象指向孤立实体时，有没有一种方法可以自动删除它？我有这两种型号…

class MyObject < ActiveRecord::Base
  belongs_to :address, :autosave => true, dependent: :destroy

class Address < ActiveRecord::Base
  has_one :my_object

在我的PostGres"my_objects"表中，我有一个"address_id"列，它是地址表的外键。以下是我用来保存"MyObject"实体及其附带地址对象的方法…

  def save_with_address(params)
    transaction do
      if !params[:address].nil?
        # Address isn't an object yet, it is just a bunch of parameters
        params[:address][:state] = params[:address][:state].nil? ? nil : State.find_by_id(params[:address][:state])
        params[:address][:country] = params[:address][:country].nil? ? nil : Country.find_by_id(params[:address][:country])
        address = Address.new(params[:address])
        address.user = self
        address.save
        self.address = address
      end
      # Save the object
      save
    end
  end

但我注意到，如果my_object实体以前有一个地址对象，那么该对象将保留在数据库中，尽管它是孤立的。调整内容以便从数据库中删除孤立地址实体的最简单方法是什么？

Answer 1

只需更新您的模型，如下

class MyObject < ActiveRecord::Base
  belongs_to :address, :autosave => true

class Address < ActiveRecord::Base
  has_one :my_object, dependent: :destroy