Question

gem 'rails', '4.2.7.1'

class Property < Accommodation  
   has_many :attachments, as: :attached_item, dependent: :destroy  
end

class Accommodation < ActiveRecord::Base;
end

class Attachment < ActiveRecord::Base
     belongs_to :attached_item, polymorphic: true
end

该关联在Rails 4.2中完全正常工作

Property.last.attachments
 Property Load (0.9ms)  SELECT  "accommodations".* FROM "accommodations" WHERE "accommodations"."type" IN ('Property')  ORDER BY "accommodations"."id" DESC LIMIT 1
 Attachment Load (0.5ms)  SELECT "attachments".* FROM "attachments" WHERE "attachments"."attached_item_id" = $1 AND "attachments"."attached_item_type" = $2  [["attached_item_id", 1], ["attached_item_type", "Property"]]

Rails 5.0中的相似关联

class CustomInquiry < ApplicationRecord;
end

class ChildInquiry < CustomInquiry  
     has_many :text_histories, as: :mailed_item, dependent: :delete_all
end

class TextHistory < ApplicationRecord
    belongs_to :mailed_item, polymorphic: true
end

2.4.0 :002 > ChildInquiry.last.text_histories
 ChildInquiry Load (1.2ms)  SELECT  "custom_inquiries".* FROM "custom_inquiries" WHERE "custom_inquiries"."type" IN ('ChildInquiry') ORDER BY "custom_inquiries"."id" DESC LIMIT $1  [["LIMIT", 1]]
 TextHistory Load (0.4ms)  SELECT "text_histories".* FROM "text_histories" WHERE "text_histories"."mailed_item_id" = $1 AND "text_histories"."mailed_item_type" = $2  [["mailed_item_id", 197], ["mailed_item_type", "CustomInquiry"]]

但是这里第二个查询应该像-

 TextHistory Load (0.4ms)  SELECT "text_histories".* FROM "text_histories" WHERE "text_histories"."mailed_item_id" = $1 AND "text_histories"."mailed_item_type" = $2  [["mailed_item_id", 197], ["mailed_item_type", "ChildInquiry"]]

任何人都可以帮助我了解Rails 5中的更新内容以及任何替代它的猴子补丁。

Answer 1

最新版本的ActiveRecord使用关联中的基类，因此，当我们使用STI时，它将采用基类而不是当前类。因此，您可以使用宝石404来解决此问题。
它将使用ActiveRecord关联中的当前类。
这是github链接

https://github.com/appfolio/store_base_sti_class

使用STI时，Rails 5.0无法获取多态关联

1 个答案: