NameError：未初始化的常量用戶

Question

我正在使用Rails作曲家的rails-devise應用程序。 在我嘗試與控制台中的模型進行交互之前，一切似乎都很好。 我嘗試了這些命令：

rails console
User.all

我從控制台收到以下錯誤：

NameError: uninitialized constant User
from (irb):2
from /Users/msarr/.rvm/gems/ruby-2.2.1/gems/railties-4.2.5.1/lib/rails/commands/console.rb:110:in `start'
from /Users/msarr/.rvm/gems/ruby-2.2.1/gems/railties-4.2.5.1/lib/rails/commands/console.rb:9:in `start'
from /Users/msarr/.rvm/gems/ruby-2.2.1/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:68:in `console'
from /Users/msarr/.rvm/gems/ruby-2.2.1/gems/railties-4.2.5.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /Users/msarr/.rvm/gems/ruby-2.2.1/gems/railties-4.2.5.1/lib/rails/commands.rb:17:in `<top (required)>'
from /Users/msarr/Desktop/deployment/YouServe/bin/rails:9:in `<top (required)>'
from /Users/msarr/.rvm/rubies/ruby-2.2.1/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from /Users/msarr/.rvm/rubies/ruby-2.2.1/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from -e:1:in `<main>'

這是我的Gemfile：

  source 'https://rubygems.org'
  ruby '2.2.1'
  gem 'rails', '4.2.5.1'
  gem 'sass-rails', '~> 5.0'
  gem 'uglifier', '>= 1.3.0'
  gem 'coffee-rails', '~> 4.1.0'
  gem 'jquery-rails'
  gem 'turbolinks'
  gem 'jbuilder', '~> 2.0'
  gem 'carrierwave'
  gem 'mini_magick'
  gem 'fog'                  
  gem 'administrate'
  gem 'devise'
  gem 'devise_invitable'
  gem 'foundation-rails', '~> 5.5'
  gem 'high_voltage'
  gem 'simple_form'

 group :development, :test do
  gem 'byebug'
  gem 'sqlite3'
end
group :development do
  gem 'web-console', '~> 2.0'
  gem 'spring'
  gem 'better_errors'
  gem 'hub', :require=>nil
  gem 'quiet_assets'
  gem 'rails_layout'
end

group :production do
 gem 'pg'
 gem 'rails_12factor'
 gem 'unicorn'
end

Answer 1

只需重新啟動彈簧加載器。

spring stop

然后運行rails c它工作正常

Answer 2

一定要在Gemfile中包含gem'depaise gem 'devise'並運行bundle

你還需要運行以下命令

rails generate devise:install
rails generate devise User
rake db:migrate

現在，您應該能夠在rails c訪問User.all

Answer 3

您項目的架構是什么樣的？ 如果您的模型（例如API或v1 ）周圍有任何模塊或命名空間，那么您必須使用命名空間調用它們，即V1::User.all 。