Ruby on rails 无法加载mysql2 gem

我已经看过了，但是没有一个对我有帮助

这就是诀窍：我必须在不接触文件的情况下修复此。我目前正在创建与生产服务器匹配的工作环境，因此根本无法修改rails的代码

我的操作系统：OSX 10.11

Ruby:Ruby 2.0.0p643

Rails:4.0.0

gem是gem文件，名为

gem'mysql2'

。执行

bundle安装时没有错误

，但是当我尝试

rake db:migrate--trace时，这是输出：

试一试

这将确保您在执行“rake db:migrate”时，gem文件中列出的gem已加载且可用。如果您在没有“bundle exec”的情况下运行它，您可能只会在系统gems可用的情况下执行。
我假设您的系统中安装了mysql，对吗？（brew安装mysql）看看这个问题：，您可能想在gemfileI中尝试“gem'mysql2'，“~>0.3.18'”。我无法修改现有的Gemfile；如上所述，我正在尝试模拟生产服务器。那么，Gemfile.lock是否与生产环境中的完全相同？
rake aborted!
There was an error while trying to load the gem 'mysql2'.
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:80:in `rescue in block (2 levels) in require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `each'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `block in require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `each'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler.rb:99:in `require'
/Users/redar/redar/config/application.rb:7:in `<top (required)>'
/Users/redar/redar/Rakefile:4:in `require'
/Users/redar/redar/Rakefile:4:in `<top (required)>'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/rake_module.rb:25:in `load'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/rake_module.rb:25:in `load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:637:in `raw_load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:94:in `block in load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:93:in `load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:77:in `block in run'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:75:in `run'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/bin/rake:33:in `<top (required)>'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/rake:23:in `load'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/rake:23:in `<main>'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/ruby_executable_hooks:15:in `eval'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/ruby_executable_hooks:15:in `<main>'

# Add your own tasks in files placed in lib/tasks ending in .rake,
# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.

require File.expand_path('../config/application', __FILE__)

MyApp::Application.load_tasks

bundle exec rake db:migrate