Ruby on Rails NameError：未初始化的常量

Ruby on Rails NameError: uninitialized constant

提问by Brian

I just set up a new migration and model relationships, and in console when testing the relationship between tables I get the following error: NameError: uninitialized constant.

我刚刚设置了一个新的迁移和模型关系，并且在控制台中测试表之间的关系时出现以下错误：NameError：未初始化的常量。

Does anyone have any idea what is wrong?

有谁知道出了什么问题？

Thank you

谢谢

Edit:

编辑：

Here's the error

这是错误

NameError: uninitialized constant Profile::ProfileNotification
  from C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:105:in `const_missing'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2199:in `compute_type'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2195:in `compute_type'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/reflection.rb:156:in `send'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/reflection.rb:156:in `klass'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/reflection.rb:187:in `quoted_table_name'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/has_many_association.rb:97:in `construct_sql'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations/association_collection.rb:21:in `initialize'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations.rb:1300:in `new'
  from C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/associations.rb:1300:in `profile_notifications'
  from (irb):3

Code from the ProfileNotification migration:

ProfileNotification 迁移中的代码：

class CreateProfileNotifications < ActiveRecord::Migration
  def self.up
    create_table :profile_notifications do |t|
      t.integer :profile_id, :null => false
      t.integer :notification_id, :null => false
      t.string :notification_text
      t.boolean :checked, :default => false
      t.boolean :update_reply, :default => false
      t.boolean :opinion_reply, :default => false
      t.boolean :message_reply, :default => false
      t.boolean :pm, :default => false
      t.boolean :accepted_friend, :default => false
      t.boolean :accepted_supporter, :default => false
      t.timestamps
    end
  end

  def self.down
    drop_table :profile_notifications
  end
end

回答by Brian

Well, I figured out the problem. When I was running ruby script/generate model, I was typing ruby script/generate model ProfileNotifications. When I typed ruby script/generate model ProfileNotification (singular) it worked. Naming conventions kill me. Thanks for all the help.

嗯，我想出了问题。当我运行 ruby​​ 脚本/生成模型时，我正在输入 ruby​​ 脚本/生成模型 ProfileNotifications。当我输入 ruby​​ 脚本/生成模型 ProfileNotification（单数）时，它起作用了。命名约定杀了我。感谢所有的帮助。

回答by Adam Lassek

It's breaking because you're referencing Profile::ProfileNotificationwhich doesn't exist.

它正在破坏，因为您正在引用Profile::ProfileNotification不存在的内容。

Rails considers this a model named ProfileNotificationlocated in the Profilenamespace, but your comment suggests that Profileis another model class and not a namespace.

Rails 认为这是一个ProfileNotification位于Profile命名空间中的模型，但您的评论表明这Profile是另一个模型类而不是命名空间。

Based on the migration you have posted, I think you're confused about the Rails naming convention for one-to-many relationships. Here's how I think it's supposed to look:

根据您发布的迁移，我认为您对一对多关系的 Rails 命名约定感到困惑。这是我认为它应该看起来的样子：

class CreateNotifications < ActiveRecord::Migration
  def self.up
    create_table :notifications do |t|
      t.references :profile
      t.text :body
      t.boolean :checked, :default => false
      t.boolean :update_reply, :default => false
      t.boolean :opinion_reply, :default => false
      t.boolean :message_reply, :default => false
      t.boolean :pm, :default => false
      t.boolean :accepted_friend, :default => false
      t.boolean :accepted_supporter, :default => false
      t.timestamps
    end
  end

  def self.down
    drop_table :notifications
  end
end

class Profile < ActiveRecord::Base
  has_many :notifications
end

class Notification < ActiveRecord::Base
  belongs_to :profile
end

Now when you execute Profile.find(1).notificationsyou should get a list of the associated notifications to that profile.

现在，当您执行时，Profile.find(1).notifications您应该会获得与该配置文件相关联的通知列表。

More information: Active Record Associations

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