Rails - 如何创建一个链接到另一个模型的TWO的模型 [英] Rails - How to create a model linked to TWO of another model

问题描述

我正在尝试创建以下内容：

I am trying to create the following:

User model (this is fine)

id

Link model (associated with two Users)

id
user_id1
user_id2

这是一个我想在链接模型上使用has_and_belongs_to_many关联类型的实例吗？我应该怎么做？

Is this an instance in which I would want to use the has_and_belongs_to_many association type on the Link model? How should I do this?

最终，我想要有一个用户对象，并调用@ user.links来获取涉及该用户的所有链接...

Ultimately, I would like to be able to have a user object and call @user.links to get all links involving that user...

我只是不知道在Rails中做什么最好的方法是。

I'm just not sure what the best way to do this in Rails is.

推荐答案

你很可能想要两个结构如下的模型：

You will very likely want two models structured as follows:

class User < ActiveRecord::Base
  has_many :friendships
  has_many :friends, :through => :friendships #...
end

class Friendship < ActiveRecord::Base
  belongs_to :user
  belongs_to :friend, :class_name => 'User', :foreign_key => 'friend_id'
end 

# ...and hence something like this in your view
<% for friendship in @user.friendships %>
  <%= friendship.status %>
  <%= friendship.friend.firstname %>
<% end %>

（此模式来自 Ryan Bates 大约两年前在这个讨论， RailsForum 。）

(This pattern is from a post made by Ryan Bates about two years ago during this discussion on RailsForum.)

只是一个注释：现在已经很老了。您可能需要考虑评估在现代Rails环境中处理此问题的其他策略。

Just a note: this is now quite old. You may want to consider evaluating other strategies for handling this in a modern Rails context.

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