MySQL 客户端库版本不正确

Question

我创建了一个新的 Rails 项目调用

rails new simple_cms 

然后在我运行的目录中时

rails s

我收到以下错误

C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/mysql2-0.3.11-x86-mingw32/l
ib/mysql2/mysql2.rb:2:in `require': Incorrect MySQL client library version! This
gem was compiled for 6.0.0 but the client library is 5.5.24. (RuntimeError)
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/mysql2-0.3.11-
x86-mingw32/lib/mysql2/mysql2.rb:2:in `<top (required)>'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/mysql2-0.3.11-
x86-mingw32/lib/mysql2.rb:9:in `require'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/mysql2-0.3.11-
x86-mingw32/lib/mysql2.rb:9:in `<top (required)>'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler/runtime.rb:68:in `require'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler/runtime.rb:68:in `block (2 levels) in require'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler/runtime.rb:66:in `each'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler/runtime.rb:66:in `block in require'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler/runtime.rb:55:in `each'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler/runtime.rb:55:in `require'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.1.3/
lib/bundler.rb:119:in `require'
    from c:/development/ruby/simple_cms/config/application.rb:7:in `<top (re
quired)>'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.3
/lib/rails/commands.rb:53:in `require'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.3
/lib/rails/commands.rb:53:in `block in <top (required)>'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.3
/lib/rails/commands.rb:50:in `tap'
    from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.3
/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

我见过其他人出现此错误，但他们往往是 linux 用户，而我正在运行 windows。我试图重新安装 rails (railsinstaller.org) 和 mysql 5.5。 32位版本和64位版本我都用过

Answer 1

这里似乎已经有几个关于此的问题。您尝试过他们的解决方案吗？

可能最清楚的是： mysql2 gem compiled for wrong mysql client library

相关部分在这里：

At the time of building this gem, the necessary DLL files where available
in the following download:

http://dev.mysql.com/get/Downloads/Connector-C/mysql-connector-c-noinstall-6.0.2-win32.zip/from/pick

And put lib\libmysql.dll file in your Ruby bin directory, for example
C:\Ruby\bin

Answer 2

这将删除 gem 及其依赖项。然后重新安装将重新编译自身和所有依赖项。

gem uninstall mysql2
bundle install

Answer 3

我在一个正在处理的新项目中遇到了这个错误，它突然停止在一台已经有可用 rails 项目的 Windows 机器上工作，所以这显然不是安装问题。

导致问题的原因是 bundle update 命令，它决定重新下载 mysql2 gem（原因不明）并忽略了我的 Gemfile 行 gem 'mysql2', '~> 0.2.6'。

问题在于，bundle update 得到了 mysql 版本 0.2.18，如 Gemfile.lock 中所示，在以下行中：

    mysql2 (0.2.18-x86-mingw32)

我注意到符号的含义，但我在我的 gemfile 中替换了以下行

gem 'mysql2', '~> 0.2.6'

为

gem 'mysql2', '0.2.6'

现在一切正常，包括bundle update。