Ruby on rails 新安装的OS X Ruby on Rails无法连接到数据库

我将先介绍一下我的规格：

• RVM 1.12.1
• 轨道3.2.3
• Ruby 1.9.3p125（2012-02-16修订版34643）[x86_64-darwin12.0.0]
• RubyGem 1.8.21
• OS X 10.8山狮
• Kenneth Reitz针对OSX 10.7+的GCC安装程序，版本2（包括X11头文件、错误修复）

我的档案如下：

source 'https://rubygems.org'
gem 'rails', '3.2.3'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'

gem 'sqlite3'


# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

    # See https://github.com/sstephenson/execjs#readme for more supported runtimes
    # gem 'therubyracer', :platform => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

我的database.yml是：

development:
  adapter: sqlite3
  database: db/development.sqlite3
  pool: 5
  timeout: 5000

当我启动服务器并转到默认主页并单击“查看环境”按钮时，我得到一个“ActiveRecord:：ConnectionNotesAblished”错误

当我检查控制台时，我看到：

/Users/username/.rvm/gems/ruby-1.9.3-p125@global/gems/bundler-1.1.3/lib/bundler/rubygems_integration.rb:147:in `block in replace_gem': Please install the mysql adapter: `gem install activerecord-mysql-adapter` (mysql is not part of the bundle. Add it to Gemfile.) (LoadError)
from /Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activerecord-3.2.3/lib/active_record/connection_adapters/mysql_adapter.rb:5:in `<top (required)>'
from /Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require'
from /Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `block in require'
from /Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:236:in `load_dependency'
from /Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require'

/Users/username/.rvm/gems/ruby-1.9.3-p125@global/gems/bundler-1.1.3/lib/bundler/rubygems_integration.rb:147:in`block in replace_gem'：请安装mysql适配器：`gem install activerecord mysql adapter`（mysql不是捆绑包的一部分。将其添加到Gemfile.）（LoadError）
来自/Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activerecord-3.2.3/lib/active\u record/connection\u adapters/mysql\u adapter.rb:5:in`'
来自/Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active\u-support/dependencies.rb:251:in'require'
来自/Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active\u support/dependencies.rb:251:in'block in require'
来自/Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active\u-support/dependencies.rb:236:in'load\u-dependency'
来自/Users/username/.rvm/gems/ruby-1.9.3-p125@rails3tutorial2ndEd/gems/activesupport-3.2.3/lib/active\u-support/dependencies.rb:251:in'require'

---

尽管我使用的是SQLite，而且在任何地方都没有对MySQL的引用。这可能是使用10.8的副作用吗？我被难住了

几个月前，我正在使用java和Play进行一个项目！框架，我们使用一个名为DATABASE_URL的环境变量在开发和生产中轻松管理数据库配置。在我的例子中，变量被设置为

mysql://root@localhost:3306/database\u name

事实证明，

rails3.2

也尝试从名为database\uurl的环境变量获取数据库配置

以下是rails 3.2分支上的代码：

rails 3.1分支上的相同方法：

---

所以我刚刚删除了环境变量，一切又恢复正常。

你确定你的应用程序中的任何地方都没有对

mysql

的引用吗，即使是在鬼鬼祟祟的地方？那里的一切看起来都很好。不，不幸的是没有。这是一个全新的、开箱即用的Rails安装。您如何启动Rails服务器？它可能试图在生产模式或其他模式下启动服务器。尝试rails s-e开发（或者查看您的rails_ENV环境变量i），rails s和rails s-e开发都会产生与上述相同的结果。我可以确认，这正是困扰我的问题。我很惊讶我们都有这样一个具体的问题。伟大的发现！