ActiveRecord :: Base的未定义方法`mysql_connection’：Class
我已经将rails2升级到rails3，当我尝试rake db：migrate时，我发现了以下错误
`rake aborted!` undefined method `mysql_connection' for ActiveRecord::Base:Class /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/dynamic_matchers.rb:55:in `method_missing' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/proxy.rb:153:in `select_connection' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/proxy.rb:215:in `method_missing' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/migration.rb:662:in `initialize' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/migration.rb:570:in `new' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/migration.rb:570:in `up' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/migration.rb:117:in `up_with_octopus' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/migration.rb:551:in `migrate' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/migration.rb:111:in `block in migrate_with_octopus' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/proxy.rb:171:in `run_queries_on_shard' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/proxy.rb:180:in `block in send_queries_to_multiple_shards' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/proxy.rb:179:in `each' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/proxy.rb:179:in `send_queries_to_multiple_shards' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/ar-octopus-0.6.1/lib/octopus/migration.rb:110:in `migrate_with_octopus' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/gems/activerecord-3.2.14/lib/active_record/railties/databases.rake:193:in `block (2 levels) in ' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/bin/ruby_executable_hooks:15:in `eval' /home/cis/.rvm/gems/ruby-1.9.3-p392@rails3214/bin/ruby_executable_hooks:15:in `' Tasks: TOP => db:migrate (See full trace by running task with --trace)` 这是我的database.yml文件开发：
适配器：mysql2
数据库：db
用户名：root
密码：
socket：/opt/lampp/var/mysql/mysql.sock
将它包含在拥有奇异字符的文件中……
#encoding: utf-8
希望这可以帮助！
谢谢大家错误是解决有gem依赖问题我有使用gem mysql2，activerecord-mysql2-adapter，mysql所以有冲突错误而不是它我只使用mysql2 gem将适配器mysql更改为mysql2