我在ROR中创建了一个简单的Web项目 - postgresql作为DB
C:\Sites\nested>ruby -v
ruby 1.9.3p484 (2013-11-22) [i386-mingw32]
C:\Sites\nested>rails -v
Rails 4.0.2
当我尝试通过命令行
添加自动外键时C:\Sites\nested>gem install automatic_foreign_key
或通过添加
编辑gem文件# create automatic foreign key
gem "automatic_foreign_key", "~> 1.3.0"
运行服务器时出现以下错误
C:\Sites\nested>rails s
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-4.0.2/lib/active_support/core_ext/module/aliasing.rb:32:in `alias_method': undefined method `to_sql' for class `ActiveRecord::ConnectionAdapters::Tab leDefinition' (NameError)
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-.0.2/lib/active_support/core_ext/module/aliasing.rb:32:in `alias_method_chain'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/redhillonrails_core-.2.0/lib/redhillonrails_core/active_record/connection_adapters/table_definition.rb:9:in `block in included'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/redhillonrails_core-.2.0/lib/redhillonrails_core/active_record/connection_adapters/table_definition.rb:6:in `class_eval'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/redhillonrails_core-.2.0/lib/redhillonrails_core/active_record/connection_adapters/table_definition.rb:6:in `included'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/redhillonrails_core-.2.0/lib/redhillonrails_core.rb:32:in `include'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/redhillonrails_core-.2.0/lib/redhillonrails_core.rb:32:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-.0.2/lib/active_support/dependencies.rb:229:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-.0.2/lib/active_support/dependencies.rb:229:in `block in require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-.0.2/lib/active_support/dependencies.rb:214:in `load_dependency'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-.0.2/lib/active_support/dependencies.rb:229:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/automatic_foreign_key-.3.0/lib/automatic_foreign_key.rb:5:in `rescue in <top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/automatic_foreign_key-.3.0/lib/automatic_foreign_key.rb:1:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler/runtime.rb:72:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler/runtime.rb:70:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler/runtime.rb:70:in `block in require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler/runtime.rb:59:in `each'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler/runtime.rb:59:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-.3.5/lib/bundler.rb:132:in require'
from C:/Sites/nested/config/application.rb:7:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-.0.2/lib/rails/commands.rb:74:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-.0.2/lib/rails/commands.rb:74:in `block in <top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-.0.2/lib/rails/commands.rb:71:in `tap'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-.0.2/lib/rails/commands.rb:71:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
答案 0 :(得分：1)
仅供参考，这是您的错误：
`alias_method': undefined method `to_sql' for class `ActiveRecord::ConnectionAdapters::Tab leDefinition' (NameError)
看起来宝石正在为.to_sql创建alias_method。 Alias方法basicaly通过另一个名称调用方法，因此您可以在不同的上下文中使用它
我们经常使用alias_method :name, :title，因为我们标准化了我们的验证，这意味着我们每次都需要保留相同的方法名称
错误
实际错误是由于您的班级没有to_sql方法造成的。我从未遇到过这种情况，所以I looked it up：
似乎Rails 4注意到这个问题。对于解决方案，我建议自automatic_foreign_key hasn't been updated since 2011以来，它将与Rails 4不兼容
如果我们把这个想法作为问题，也许你可以详细说明你希望它如何工作＆amp;我们可以创建一个解决方法吗？
答案 1 :(得分：0)
试试这个
C:\Sites\nested>gem install --local automatic_foreign_key
以及项目终端中的bundle install --local，然后在您的gem文件中修改gem "automatic_foreign_key", "~> 1.3.0"