rails mysql适配器错误答案

【问题标题】：rails mysql adapter errorrails mysql适配器错误
【发布时间】：2011-05-26 15:42:37
【问题描述】：

我无法找到解决此问题的方法。我收到了错误

请安装mysql适配器：'gem install activerecord-mysql-adapter'

当我在 Gemfile 中指定 ruby-mysql 或 mysql2 时。这只是在我升级到 Rails 3.1.0-rc1 后才发生的。我正在运行 OSX 10.6、Ruby 1.9.2。

cody$ rails c
/Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:71:in `rescue in establish_connection': Please install the mysql adapter: `gem install activerecord-mysql-adapter` (mysql is not part of the bundle. Add it to Gemfile.) (RuntimeError)
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:68:in `establish_connection'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:60:in `establish_connection'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/connection_adapters/abstract/connection_specification.rb:55:in `establish_connection'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/railtie.rb:69:in `block (2 levels) in <class:Railtie>'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.0.rc1/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.0.rc1/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.0.rc1/lib/active_support/lazy_load_hooks.rb:43:in `block in run_load_hooks'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.0.rc1/lib/active_support/lazy_load_hooks.rb:42:in `each'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.1.0.rc1/lib/active_support/lazy_load_hooks.rb:42:in `run_load_hooks'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/base.rb:2135:in `<top (required)>'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc1/lib/active_record/railtie.rb:34:in `block in <class:Railtie>'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/railtie.rb:177:in `call'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/railtie.rb:177:in `block in load_console'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/railtie.rb:177:in `each'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/railtie.rb:177:in `load_console'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/application.rb:115:in `block in load_console'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/application/railties.rb:8:in `each'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/application/railties.rb:8:in `all'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/application.rb:115:in `load_console'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/commands/console.rb:26:in `start'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/commands/console.rb:8:in `start'
from /Users/cody/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.1.0.rc1/lib/rails/commands.rb:40:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'

这是gem env 输出

cody$ gem env
RubyGems Environment:
- RUBYGEMS VERSION: 1.6.2
- RUBY VERSION: 1.9.2 (2011-02-18 patchlevel 180) [x86_64-darwin10.7.3]
- INSTALLATION DIRECTORY: /Users/cody/.rvm/gems/ruby-1.9.2-p180
- RUBY EXECUTABLE: /Users/cody/.rvm/rubies/ruby-1.9.2-p180/bin/ruby
- EXECUTABLE DIRECTORY: /Users/cody/.rvm/gems/ruby-1.9.2-p180/bin
- RUBYGEMS PLATFORMS:
  - ruby
  - x86_64-darwin-10
- GEM PATHS:
   - /Users/cody/.rvm/gems/ruby-1.9.2-p180
   - /Users/cody/.rvm/gems/ruby-1.9.2-p180@global
- GEM CONFIGURATION:
   - :update_sources => true
   - :verbose => true
   - :benchmark => false
   - :backtrace => false
   - :bulk_threshold => 1000
   - :sources => ["http://gems.rubyforge.org/", "http://gems.github.com"]
- REMOTE SOURCES:
   - http://gems.rubyforge.org/
   - http://gems.github.com

【问题讨论】：

我相信我已经解决了我的问题。我在 database.yml 中设置了`适配器：mysql2`而不是`适配器：mysql` 我为噪音道歉。
建议原发帖者接受 Brad Folkens 的回答

标签： mysql ruby-on-rails-3.1

【解决方案1】：

您必须更改您的config/database.yml 以使用mysql2 适配器而不是mysql。

所以替换：

adapter: mysql

与：

adapter: mysql2

【讨论】：

对在 Heroku 上使用 Amazon RDS 插件的任何人的说明，您需要进行此更改，并将 RDS 插件中的数据库 URL 更改为使用 mysql2:// 而不是 @987654327 @ 否则你仍然会得到错误。

【解决方案2】：

我必须强制使用 mysql2 gem 版本 0.2.7，并且在尝试将我的 rails 3.0.7 应用程序升级到 3.1.0.rc1 时，我还注意到，您的 Gemfile 中需要以下新 gem ，也：

gem 'mysql2', '< 0.3' # as stated above

# Asset template engines
gem 'json'
gem 'sass'
gem 'coffee-script'
gem 'uglifier'
# other required things for rails 3.1
gem 'jquery-rails'
gem 'mustang' # this is ONE execjs backend of many, and the only one that worked for me.

告诉我这是否对你有用。

【讨论】：

有什么理由将 gem 版本限制为 '

【解决方案3】：

通过更新我的应用程序的 gemfile 以将 mysql2 识别为捆绑包的一部分来解决问题。

为此，导航到应用的根目录，运行open gemfile

将gem 'mysql2', '< 0.3.7' 行添加到rails gem 行的正下方。

在应用程序根目录的终端中，运行bundle install

运行bundle show mysql2 以验证捆绑包是否有效。您现在应该可以使用适配器了。

我的环境是 Rails 3.1、MySql 5.5、Ruby 1.9.2。

【讨论】：

【解决方案4】：

我在 Windows 上创建了一个 Rails 项目，并将其移动到运行 Fedora 的机器上。我通过将“Gemfile.lock”重命名为“old_Gemfile.lock”解决了这个问题。当然，您仍然必须将适配器指定为 'mysql2' 并在 gemfile 中包含适当的 gem。

【讨论】：