未初始化的常量ApplicationRecord
[英]uninitialized constant ApplicationRecord
问题描述
I am working on the rails tutorial book online and I am getting the following error message when I go to http://localhost:3000/ 
我正在线上的rails教程书，当我转到http：// localhost：3000 /时，我收到以下错误消息
"uninitialized constant ApplicationRecord"
and it gives me the following code highlighting the first line. 它给了我以下代码突出显示第一行。
class User < ApplicationRecord attr_accessor :remember_token before_save { self.email = email.downcase } validates :name, presence: true, length: { maximum: 50 } VALID_EMAIL_REGEX = /\\A[\\w+\\-.]+@[az\\d\\-.]+\\.[az]+\\z/i validates :email, presence: true, length: { maximum: 255 },
Here is my application.html.erb file: 这是我的application.html.erb文件：
<!DOCTYPE html> <html> <head> <title><%= full_title(yield(:title)) %></title> <%= stylesheet_link_tag "application", media: "all", "data-turbolinks-track" => true %> <%= javascript_include_tag "application", "data-turbolinks-track" => true %> <%= csrf_meta_tags %> <%= render 'layouts/shim' %> </head> <body> <%= render 'layouts/header' %> <div class="container"> <% flash.each do |message_type, message| %> <div class="alert alert-<%= message_type %>"><%= message %></div> <% end %> <%= yield %> <%= render 'layouts/footer' %> <%= debug(params) if Rails.env.development? %> </div> </body> </html>
And my user.rb file : 和我的user.rb文件：
class User < ApplicationRecord attr_accessor :remember_token before_save { self.email = email.downcase } validates :name, presence: true, length: { maximum: 50 } VALID_EMAIL_REGEX = /\\A[\\w+\\-.]+@[az\\d\\-.]+\\.[az]+\\z/i validates :email, presence: true, length: { maximum: 255 }, format: { with: VALID_EMAIL_REGEX }, uniqueness: { case_sensitive: false } has_secure_password validates :password, presence: true, length: { minimum: 6 } # Returns the hash digest of the given string. def User.digest(string) cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST : BCrypt::Engine.cost BCrypt::Password.create(string, cost: cost) end # Returns a random token. def User.new_token SecureRandom.urlsafe_base64 end # Remembers a user in the database for use in persistent sessions. def remember self.remember_token = User.new_token update_attribute(:remember_digest, User.digest(remember_token)) end # Returns true if the given token matches the digest. def authenticated?(remember_token) return false if remember_digest.nil? BCrypt::Password.new(remember_digest).is_password?(remember_token) end # Forgets a user. def forget update_attribute(:remember_digest, nil) end end
3 个解决方案
解决方案1
19 已采纳 2016-07-12 01:53:09
It appears you're using the Rails 5 tutorial, but working with Rails 4. In Rails 5 all models inherit from ApplicationRecord , while Rails 4 from ActiveRecord::Base 看来你正在使用Rails 5教程，但是使用Rails 4.在Rails 5中，所有模型都继承自ApplicationRecord ，而Rails 4则来自ActiveRecord::Base
Immediate fix: 立即修复：
class User < ActiveRecord::Base
...
end
Long term fix, switch to Rails 5 and learn with Rails 5 长期修复，切换到Rails 5并学习Rails 5
解决方案2
11 2017-08-05 21:54:38
Referring to infused's answer from https://stackoverflow.com/a/41388844/5598043 参考https://stackoverflow.com/a/41388844/5598043的注入答案
Create a new file called app/models/application_record.rb with the following content: 使用以下内容创建名为app/models/application_record.rb的新文件：
class ApplicationRecord < ActiveRecord::Base
self.abstract_class = true
end
解决方案3
0 2019-09-09 15:18:54
If you are getting this after moving from Rails 5 to Rails 6, ensure you change 如果从Rails 5转移到Rails 6后得到这个，请确保更改
config.load_defaults 5.2
for 对于
config.load_defaults 6.0
in your config/application.rb file. 在您的config/application.rb文件中。
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