Question

尝试在我的连接表中创建记录时出现此错误

中的NameError   SubscriptionsController＃新

未初始化的常量   通道:: ChannelsUser

订阅控制器

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

用户模型

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

频道模型

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

您的频道用户类名称是复数。它应该是单数。

所以你可以改为：

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

或在User和Channel型号中更改此行：

has_many :channels_users

到

has_many :channels_users, :class_name => 'ChannelsUsers'

Rails将使用String#classify和String#underscore等方法来检测类和关系。

如果您想使用这些名称，请在控制台中尝试各种组合：

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

Answer 2

如果将模型更改为ChannelUser，这会更好。以下是相应的关系：

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

然后，您的联接表将被称为channel_users。我认为你最初将它命名为channels_users，因为这是has_and_belongs_to_many连接表的设置。但是，由于您使用的是has_many :through，因此您可以随意命名表格。

我在今年早些时候撰写了一篇博客文章，详细介绍了所有选项：

Basic Many-to-Many Associations in Rails

我希望这有帮助！

控制器中的命名错误

2 个答案: