建立用户“友谊”模型的最佳方式 与不同的实体？
我有以下实体：
- 用户
- 、公司
- 、组织
用户需要能够将用户、公司、组织和未来的聚会对象添加到他们的朋友列表中。
我最初的想法涉及使用与朋友具有多态关系的 Friendship 对象，如下所示：
的 Friendship 模式：
- user_idfriendable_idfriendable_type
- 简化
- 我的
User - has_many :businesses, :through => :friendships, :conditions => ['friendable_type=?', 'Business'], :source => :friendable
问题是 Ruby on Rails ActiveRecord 不支持通过连接表上的多态关系来实现 has_many 关系。
最后，我希望有一个连接表，能够迭代以获取所有类型、某些类型等的朋友列表，如下所示：
john = User.find(5)
john.friendships.map {|friendship| friendship.friendable }
john.businesses (has_many :through scoped to only the businesses)
john.organizations (has_many :through scoped only to the organizations)
我考虑过让用户、业务和组织继承自通用 Party 类并使关联指向基 Party 类，但在 ORM 的上下文中会导致一堆垃圾字段，而且看起来很脏。
我想知道的是其他人将如何处理这样的情况，您希望使用 ActiveRecord 通过公共联接表创建与相似对象的一对多关系，同时避免此错误::)
Cannot have a has_many :through association 'User#businesses' on the polymorphic object 'Friendship#friendable'.
非常感谢任何建议。
谢谢！
I have the following entities:
- User
- Company
- Organization
Users need to be able to add Users, Companies, Organizations, and future party objects to their friend list.
My original idea involved using a Friendship object with a polymorphic relationship to the friend like so:
Simplified Friendship schema:
- user_id
- friendable_id
- friendable_type
User - has_many :businesses, :through => :friendships, :conditions => ['friendable_type=?', 'Business'], :source => :friendable
My problem is that Ruby on Rails ActiveRecord does not support has_many through relationships through polymorphic relationships on the join table such.
In the end I want to have a single join table to be able to iterate through to get a list of friends of all types, certain types, etc. like below:
john = User.find(5)
john.friendships.map {|friendship| friendship.friendable }
john.businesses (has_many :through scoped to only the businesses)
john.organizations (has_many :through scoped only to the organizations)
I've considered making the User, Business, and Organization inherit from a generic Party class and making the association point to the base Party class, but in the context of an ORM that leads to a bunch of junk fields and it just seems dirty.
What I'd like to know is how others would approach a situation like this where you want to create one-to-many relationships to similar objects through a common join table using ActiveRecord while avoiding this error: :)
Cannot have a has_many :through association 'User#businesses' on the polymorphic object 'Friendship#friendable'.
Any advice greatly appreciated.
Thanks!
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在多态 has_many 关系中不要使用 :through，而是使用 :as=>friendable
Do not use :through, use :as=>friendable instead in polymorphic has_many relationship
看来 Rails 插件“has_many_polymorphs”允许我完全按照我的意愿去做。
http://github.com/fauna/has_many_polymorphs/tree/master
将此行添加到我的用户模型中为我提供了我想要的功能：
It appears that the Rails plugin 'has_many_polymorphs' allows me to do exactly what I want.
http://github.com/fauna/has_many_polymorphs/tree/master
Adding this line to my User model gave me the functionality I wanted: