在控制器

Question

命名的錯誤，我想在我加入表

NameError在 SubscriptionsController＃新

未初始化的常量 頻道:: ChannelsUser

創建一個記錄時出現此錯誤訂閱控制器

class SubscriptionsController < ApplicationController 

    helper_method :current_user_session, :current_user 
    filter_parameter_logging :password, :password_confirmation 

    def new 
    @channel = Channel.find(params[:channel_id]) 
    @user = current_user 
    @channel.subscribers << @user 
    @channel.save 
    flash[:notice] = "You have subscribed to: " +@channel.name 
    redirect_to @channel 
    end 

end 

端

用戶模型

class User < ActiveRecord::Base 

    acts_as_authentic 

    ROLES = %w[admin moderator subscriber] 

    #Each user can subscribe to many channels 
    has_many :channels_users 
    has_many :subscriptions, :class_name => "Channel", :through => :channels_users 

    #Each user who is a moderator can moderate many channels 
    has_many :channel_mods 
    has_many :channels, :through => :channel_mods 

    #Each user can receive many messages 
    has_many :messages_users , :dependent => :destroy 
    has_many :reciepts , :class_name => "User", :through => :messages_users 

    #Filter users by role(s) 
    named_scope :with_role, lambda { |role| {:conditions => "roles_mask & #{2**ROLES.index(role.to_s)} > 0 "} } 

    def roles 
    ROLES.reject { |r| ((roles_mask || 0) & 2**ROLES.index(r)).zero? } 
    end 

    def roles=(roles) 
    self.roles_mask = (roles & ROLES).map { |r| 2**ROLES.index(r) }.sum 
    end 

    def role_symbols 
    role.map do |role| 
     role.name.underscore.to_sym 
    end 
    end 

end 

信道模型

class Channel < ActiveRecord::Base 
    #Each channel owns many or no messages 
    has_many :messages 
    #Each channel is own by one moderator 
    has_many :channel_mods 
    has_many :moderators, :class_name =>'User', :through =>:channel_mod 
    #Each channel can have and belong to many or no users 
    has_many :channels_users 
    has_many :subscribers, :class_name => 'Users' , :through => :channels_users 

end 

ChannelsUsers模型

class ChannelsUsers < ActiveRecord::Base 
    belongs_to :user 
    belongs_to :channel 
end 

Answer 1

如果更改模型ChannelUser這會讀更好。以下是相應的關係：

class Channel < ActiveRecord::Base 
    has_many :channel_users 
    has_many :users, :through => :channel_users 
end 

class User < ActiveRecord::Base 
    has_many :channel_users 
    has_many :channels, :through => :channel_users 
end 

class ChannelUser < ActiveRecord::Base 
    belongs_to :channel 
    belongs_to :user 
end 

您的連接表然後將被稱爲channel_users。我想你最初命名爲channels_users，因爲這是has_and_belongs_to_many連接表的設置。但是由於您使用的是has_many :through，因此您可以隨意爲其命名。

我在今年年初寫了一篇博客文章，通過詳細所有選項散步：

Basic Many-to-Many Associations in Rails

我希望這有助於！

Answer 2

你的信道用戶類別名稱是一個複數。它應該是單數。

所以，要麼你可以改成這樣：

class ChannelsUser < ActiveRecord::Base 
    belongs_to :user 
    belongs_to :channel 
end 

或更改此行User和Channel型號：

has_many :channels_users 

到

has_many :channels_users, :class_name => 'ChannelsUsers' 

Rails會使用類似的方法String#classify和String#underscore檢測t類和關係。

如果你要玩的名稱，在控制檯中嘗試不同的組合：

>> "channels_users".classify 
=> "ChannelsUser" 
>> "ChannelsUser".underscore 
=> "channels_user"