Ruby on Rails雙向關聯

Question

我試圖在rails應用程序的ruby中實現以下功能。這也是我的數據庫佈局和型號名稱。

但是，這不是真的爲我工作。

用戶模式：

class User < ActiveRecord::Base 
    has_many :follows 
    has_many :users, :through => :follows 
end 

後續型號：

class Follow < ActiveRecord::Base 
    belongs_to :user, :foreign_key => :follow_user_id 
end 

我用這個調試：

<% current_user.follows.each do |x| %> 
    <%= debug x.user %> 
<% end %> 

我不知道如何做到這一點另一種方式是a我甚至不確定我是否正確地做這件事。任何幫助讚賞。

Answer 1

你有正確的想法，你只是沒有完成的協會。首先，請注意，用戶連接兩次以遵循 - 每個方向一次。

rails g model User email:string name:string 
rails g model Follow user:references follow_user:references 

然後：

class User < ActiveRecord::Base 
    has_many :follows, inverse_of: :user 
    has_many :followers, through: :follows 

    has_many :followings, class_name: 'Follow', foreign_key: :follow_user_id, inverse_of: :follower 
    has_many :users_i_follow, through: :followings, source: :user 
end 

class Follow < ActiveRecord::Base 
    belongs_to :user, inverse_of: :follows 
    belongs_to :follower, inverse_of: :followers, class_name: 'User', foreign_key: :follow_user_id 
end 

現在，對於用戶有兩個協會，你可能主要使用： 「追隨者」 和 「users_i_follow」。

mdchaney$ bundle exec rails c 
Loading development environment (Rails 4.1.5) 
2.1.1 :001 > u = User.create(:email => 'test@comor.net', :name => 'Leader Guy') 
=> #<User id: 1, email: "test@comor.net", name: "Leader Guy", created_at: "2014-09-26 18:48:52", updated_at: "2014-09-26 18:48:52"> 

2.1.1 :002 > u2 = User.create(:email => 'follower@comor.net', :name => 'Follower Guy') 
=> #<User id: 2, email: "follower@comor.net", name: "Follower Guy", created_at: "2014-09-26 18:49:13", updated_at: "2014-09-26 18:49:13"> 

2.1.1 :003 > u3 = User.create(:email => 'follower3@comor.net', :name => 'Follower Guy, III') 
=> #<User id: 3, email: "follower3@comor.net", name: "Follower Guy, III", created_at: "2014-09-26 18:49:25", updated_at: "2014-09-26 18:49:25"> 

2.1.1 :004 > u.followers 
=> #<ActiveRecord::Associations::CollectionProxy []> 

2.1.1 :005 > Follow.create(:user => u, :follower => u2) 
=> #<Follow id: 1, user_id: 1, follow_user_id: 2, created_at: "2014-09-26 18:50:12", updated_at: "2014-09-26 18:50:12"> 

2.1.1 :006 > Follow.create(:user => u, :follower => u3) 
=> #<Follow id: 2, user_id: 1, follow_user_id: 3, created_at: "2014-09-26 18:50:14", updated_at: "2014-09-26 18:50:14"> 

2.1.1 :007 > u = User.find(1) 
=> #<User id: 1, email: "test@comor.net", name: "Leader Guy", created_at: "2014-09-26 18:48:52", updated_at: "2014-09-26 18:48:52"> 

2.1.1 :008 > u.followers 
=> #<ActiveRecord::Associations::CollectionProxy [#<User id: 2, email: "follower@comor.net", name: "Follower Guy", created_at: "2014-09-26 18:49:13", updated_at: "2014-09-26 18:49:13">, #<User id: 3, email: "follower3@comor.net", name: "Follower Guy, III", created_at: "2014-09-26 18:49:25", updated_at: "2014-09-26 18:49:25">]> 

2.1.1 :009 > u.follows 
=> #<ActiveRecord::Associations::CollectionProxy [#<Follow id: 1, user_id: 1, follow_user_id: 2, created_at: "2014-09-26 18:50:12", updated_at: "2014-09-26 18:50:12">, #<Follow id: 2, user_id: 1, follow_user_id: 3, created_at: "2014-09-26 18:50:14", updated_at: "2014-09-26 18:50:14">]> 

2.1.1 :010 > u2 = User.find(2) 
=> #<User id: 2, email: "follower@comor.net", name: "Follower Guy", created_at: "2014-09-26 18:49:13", updated_at: "2014-09-26 18:49:13"> 

2.1.1 :011 > u2.followers 
=> #<ActiveRecord::Associations::CollectionProxy []> 

2.1.1 :012 > u2.follows 
=> #<ActiveRecord::Associations::CollectionProxy []> 

2.1.1 :013 > u2.followings 
=> #<ActiveRecord::Associations::CollectionProxy [#<Follow id: 1, user_id: 1, follow_user_id: 2, created_at: "2014-09-26 18:50:12", updated_at: "2014-09-26 18:50:12">]> 

2.1.1 :014 > u2.users_i_follow 
=> #<ActiveRecord::Associations::CollectionProxy [#<User id: 1, email: "test@comor.net", name: "Leader Guy", created_at: "2014-09-26 18:48:52", updated_at: "2014-09-26 18:48:52">]>