未定义的方法raise_in_transactional_callbacks ='for ActiveRecord :: Base:Class(NoMethodError)

Question

在写这个问题之前,我查看了这些答案,但无法找到解决方案:

执行rails生成脚手架时出错用户名:string email:string

耙子流产了!用于ActiveRecord :: Base的未定义方法`migration_error =':Class

启动Rails服务器时出错:未定义方法'configure'

---

当我尝试启动一个新的应用程序(对于 Hartl的教程,第2章),在阶段脚手架开始时,我得到一个错误,如:

**undefined method `configure' for #<SampleApp2::Application:0x00000101a74610> (NoMethodError)**

但是由于上面的例子,我编辑了development.rb文件:

DemoApp::Application.configure do

(是的,我的应用程序名为demo_app,所以我改名了).

之后,我尝试再次运行scaffold,但遇到了一个新错误:

**method_missing': undefined method raise_in_transactional_callbacks=' for ActiveRecord::Base:Class (NoMethodError)**

对类似情况的回应表明了一种迁移方法 - 它应该从文件development.rb中删除.同样,我试图在这个文件中找到raise_in_transactional_callbacks方法,但它不存在!另外,我会说在cmd中生成的完整代码非常大:

C:\Sites\demo_app>rails generate scaffold User name:string email:string
invoke  active_record
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-4.0.2/lib/active_record/dynamic_matchers.rb:22:in `method_missing': undefined method `raise_in_transactional_callbacks=' for ActiveRecord::Base:Class (NoMethodError)
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-4.0.2/lib/active_record/railtie.rb:166:in `block (3 levels) in <class:Railtie>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-4.0.2/lib/active_record/railtie.rb:165:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activerecord-4.0.2/lib/active_record/railtie.rb:165:in `block (2 levels) in <class:Railtie>'
…
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-4.0.2/lib/rails/commands.rb:48:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'

哪里...(省略号) - 特别切割类似的代码.就这样.我将不胜感激任何帮助!

Answer 1

你config/application.rb有以下几行:

config.active_record.raise_in_transactional_callbacks = true

这不是您的Rails版本中的有效配置值.您需要删除它或将其注释以继续.

注意:此错误和继续执行的错误表示Rails版本更改不完整.如果您处于教程的早期阶段,您可能会认真考虑从一开始就使用首选版本的Rails重新启动应用程序.在您更熟悉该技术之前,这将帮助您避免此类错误.

Answer 2

将应用程序从Rails 5.0.1升级到Rails 5.1.0.beta1时,我遇到了同样的问题.

启动服务器(rails s)时,我收到以下错误消息:

/home/user01/.rvm/gems/ruby-2.4.0@global/gems/activerecord-5.1.0.beta1/lib/active_record/dynamic_matchers.rb:22:in `method_missing': undefined method `raise_in_transactional_callbacks=' for ActiveRecord::Base:Class (NoMethodError)

同样的弊病,同样的治疗方法.

评论出以下一行config/application.rb,解决了这个问题......

config.active_record.raise_in_transactional_callbacks = true

经过一番调查,我发现这行是Rails 4.2.1中的默认行,在Rails 5.0.0中消失了,现在在Rails 5.1.0.beta1中引发错误......