Ruby on Rails Michael Hartl第6.1.3章

Question

在教程中加載沙盒中的Rails控制檯時，我無法創建新的用戶對象？我有這個消息：

>> User.new 

NameError: uninitialized constant User 
    from (irb):1 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/railties-4.1.5/lib/rails/commands/console.rb:90:in `start' 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/railties-4.1.5/lib/rails/commands/console.rb:9:in `start' 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/railties-4.1.5/lib/rails/commands/commands_tasks.rb:69:in `console' 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/railties-4.1.5/lib/rails/commands/commands_tasks.rb:40:in `run_command!' 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/railties-4.1.5/lib/rails/commands.rb:17:in `<top (required)>' 
    from /Users/Genosia/code/sample_app/bin/rails:8:in `<top (required)>' 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require' 
    from /Users/Genosia/.rbenv/versions/2.1.2/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require' 
    from -e:1:in `<main>' 

Answer 1

你的app/models文件夾中必須有一個用戶類。

您可以使用該軌道發生器：

bundle exec rails g model user name:string date_of_birth:date ... 

，將創建db/migrate

下app/models下的模型，並在遷移到運行遷移運行

bundle exec rake db:migrate 
bundle exec rails c --sandbox 

然後應該管用。

請注意，在沙盒模式下打開控制檯時，將關閉它時會回滾所有數據庫更改。

要具有持續性的改變運行

bundle exec rails c