Question

我有以下配置：

linux ubuntu 11.04
rails 3.0.9
ruby 1.9.2p290
mysql2（0.2.7）

我使用“rails new”首先创建了我的项目然后我修改了Gemfile以使用mysql2版本0.2.7（我已经读过以后的版本只使用rails 3.1）然后我将文件database.yml更改为使用mysql2而不是sqlite3 但是，当我尝试连接到Controller时，我收到错误 ActiveRecord :: ConnectionNotEstablished 。以下是完整的日志：

activerecord (3.0.9) lib/active_record/connection_adapters/abstract/connection_pool.rb:317:in `retrieve_connection'
activerecord (3.0.9) lib/active_record/connection_adapters/abstract/connection_specification.rb:97:in `retrieve_connection'
activerecord (3.0.9) lib/active_record/connection_adapters/abstract/connection_specification.rb:89:in `connection'
activerecord (3.0.9) lib/active_record/query_cache.rb:12:in `cache'
activerecord (3.0.9) lib/active_record/query_cache.rb:31:in `call'
activerecord (3.0.9) lib/active_record/connection_adapters/abstract/connection_pool.rb:354:in `call'
actionpack (3.0.9) lib/action_dispatch/middleware/callbacks.rb:46:in `call'
activesupport (3.0.9) lib/active_support/callbacks.rb:416:in `_run_call_callbacks'
actionpack (3.0.9) lib/action_dispatch/middleware/callbacks.rb:44:in `call'
rack (1.2.3) lib/rack/sendfile.rb:107:in `call'
actionpack (3.0.9) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.0.9) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.0.9) lib/rails/rack/logger.rb:13:in `call'
rack (1.2.3) lib/rack/runtime.rb:17:in `call'
activesupport (3.0.9) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.2.3) lib/rack/lock.rb:11:in `call'
rack (1.2.3) lib/rack/lock.rb:11:in `synchronize'
rack (1.2.3) lib/rack/lock.rb:11:in `call'
actionpack (3.0.9) lib/action_dispatch/middleware/static.rb:30:in `call'
railties (3.0.9) lib/rails/application.rb:168:in `call'
railties (3.0.9) lib/rails/application.rb:77:in `send'
railties (3.0.9) lib/rails/application.rb:77:in `method_missing'
railties (3.0.9) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.2.3) lib/rack/content_length.rb:13:in `call'
rack (1.2.3) lib/rack/handler/webrick.rb:52:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
/usr/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
/usr/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
/usr/lib/ruby/1.8/webrick/server.rb:95:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `each'
/usr/lib/ruby/1.8/webrick/server.rb:92:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:23:in `start'
/usr/lib/ruby/1.8/webrick/server.rb:82:in `start'
rack (1.2.3) lib/rack/handler/webrick.rb:13:in `run'
rack (1.2.3) lib/rack/server.rb:217:in `start'
railties (3.0.9) lib/rails/commands/server.rb:65:in `start'
railties (3.0.9) lib/rails/commands.rb:30
railties (3.0.9) lib/rails/commands.rb:27:in `tap'
railties (3.0.9) lib/rails/commands.rb:27
script/rails:6:in `require'
script/rails:6

PS：我尝试了本网站提供的几乎所有解决方案，但我仍有同样的问题。

Answer 1

我最后用命令

重新创建了一个新项目

rails new -d mysql

现在可以毫无问题地检索页面！我试图比较自动database.yml文件和手动文件，我注意到的唯一不同之处在于用于mysql数据库的用户。在新的用户名中使用root：我回到旧项目，我改为使用root用户名/密码我现在正在工作！

Answer 2

我猜你的database.yml文件不正确。看起来应该是这样的：

development:
  adapter: mysql2
  host: localhost 
  username: root
  password: xxxx
  database: xxxx

如果不起作用，请尝试将localhost更改为127.0.0.1

Rails使用mysql2而不是sqlite3

2 个答案: