Mac OS X 上的 MySql2 on Rails 3.0.3

Question

我知道这个问题已经被不同的其他用户多次询问过类似的问题，但我似乎找不到与我的情况相似的问题:

我的规范:

OS - Mac OSX 10.6 Snowleopard
SQL Server - MySQL 5.5
Rails - 3.0.3
Ruby 1.8.7

在尝试运行 rake db:create 时，我遇到了以下错误消息:

"uninitialized constant Mysql2" 

如果您有兴趣，可以发布完整的跟踪:-

** Invoke db:create (first_time)
** Invoke db:load_config (first_time)
** Invoke rails_env (first_time)
** Execute rails_env
** Execute db:load_config
** Execute db:create
rake aborted!
uninitialized constant Mysql2
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.3/lib/active_record/railties/databases.rake:64:in `create_database'
/Library/Ruby/Gems/1.8/gems/activerecord-3.0.3/lib/active_record/railties/databases.rake:33
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31
/usr/bin/rake:19:in `load'
/usr/bin/rake:19

Answer 1

同样的配置，同样的问题...

编辑:已解决!必须将 gem 'mysql2' 添加到 Gemfile 并运行 bundle install。现在它工作正常。