我该怎么做的ActiveRecord的反身自联接关系？ [英] How do I do reflexive self-join relationships in ActiveRecord?

问题描述

我想实现一个社交式的友谊模式，我没有太多的运气，试图找出插件可用在那里。我想我会学习Rails的更好，如果我做我自己。所以，这里是我的：

 类用户的LT;的ActiveRecord :: Base的
  的has_many：invitee_friendships，
           ：foreign_key =＆GT; ：friend_id，
           ：将class_name =＆GT; '友谊'

  的has_many：inviter_friends，
            ：通过=＆GT; ：invitee_friendships

  的has_many：inviter_friendships，
           ：foreign_key =＆GT; ：用户帐号，
           ：将class_name =＆GT; '友谊'

  的has_many：invited_friends，
            ：通过=＆GT; ：inviter_friendships

结束

一流的友谊＆LT;的ActiveRecord :: Base的
  belongs_to的：用户
  //我认为有些事情需要到这里来，我不知道是什么
结束
 

在 IRB 当我尝试这样的：

  friend1 = Friend.create（：名称=＆GT;'杰克'）
friend2 = Friend.create（：名称=＆GT;约翰）
BFF = Friendship.create（：USER_ID =大于1，：friend_id =→2）
f1.invited_friends
 

我得到一个错误：

 的ActiveRecord :: HasManyThroughSourceAssociationNotFoundError：
无法找到源
联想（S）：invited_friend或
：在模型中友谊invited_friends。
试试'的has_many：invited_friends，
：通过=＆GT; ：invited_friendships，
：源=＆GT; ＆LT;名称＆gt;。它是一个
：用户？
 

友谊体系Expanation：

• 的用户可以邀请其他用户成为朋友。
通过 invited_friends psented
• 您邀请谁成为朋友用户重新$ P $。
• 谁邀请你的用户成为朋友是通过 inviter_friends psented重新$ P $。
通过 invited_friends + inviter_friends psented
• 您的总好友列表重新$ P $。

模式

 表友谊
      t.integer：USER_ID
      t.integer：friend_id
      t.boolean：invite_accepted
      t.timestamps

表用户
    t.string：名称
    t.string：描述
 

解决方案

我很惊讶，没有人提到最近瑞安贝茨的的在话题:)截屏

希望这有助于！

这是瑞安摘录......需要在用户模型中的自我指涉协会定义的朋友/追随者

I'm trying to implement a social networking style friendship model and I didnt have much much luck trying to figure out the plugins available out there. I think I'll learn Rails better if I do it myself. So here's what I have :

class User < ActiveRecord::Base
  has_many :invitee_friendships ,
           :foreign_key => :friend_id,
           :class_name => 'Friendship'

  has_many :inviter_friends,
            :through => :invitee_friendships

  has_many :inviter_friendships ,
           :foreign_key => :user_id,
           :class_name => 'Friendship'

  has_many :invited_friends,
            :through => :inviter_friendships

end

class Friendship < ActiveRecord::Base
  belongs_to :user
  //I think something needs to come here, i dont know what
end

In irb when I try this:

friend1  = Friend.create(:name => 'Jack')
friend2  = Friend.create(:name => 'John')
bff = Friendship.create(:user_id =>1, :friend_id => 2)
f1.invited_friends

I get an error:

ActiveRecord::HasManyThroughSourceAssociationNotFoundError:
Could not find the source
association(s) :invited_friend or
:invited_friends in model Friendship. 
Try 'has_many :invited_friends,
:through => :invited_friendships,
:source => <name>'.  Is it one of
:user?

Expanation of friendship system:

• A user can invite other users to become friends.
• Users who you invited to become friends are represented by invited_friends.
• Users who invited you to become friends are represented by inviter_friends.
• Your total friend list is represented by invited_friends + inviter_friends.

Schema

table Friendship
      t.integer :user_id
      t.integer :friend_id
      t.boolean :invite_accepted
      t.timestamps

table User
    t.string :name
    t.string :description

解决方案

I'm surprised no one has pointed to the recent Ryan Bates's screencast on the topic :)

Hope this helps!.

Excerpt from Ryan '... requires a self-referential association on the User model to define friends/followers'

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