我在Rails 3中进行数据库迁移时遇到异常.
undefined method `visitor' for #<ActiveRecord::ConnectionAdapters::MysqL2Adapter:0x00000103dea3d8>
编辑
在我的项目中没有出现字符串访问者所以我很困惑.
这是完整的转储：
$rake db:migrate --trace ** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Invoke db:load_config (first_time) ** Invoke rails_env (first_time) ** Execute rails_env ** Execute db:load_config ** Execute db:migrate rake aborted! undefined method `visitor' for #<ActiveRecord::ConnectionAdapters::MysqL2Adapter:0x00000103dea3d8> .rvm/gems/ruby-1.9.2-p180/gems/arel-2.1.5/lib/arel/tree_manager.rb:19:in `visitor' .rvm/gems/ruby-1.9.2-p180/gems/arel-2.1.5/lib/arel/tree_manager.rb:23:in `to_sql' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:562:in `get_all_versions' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:708:in `migrated' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:635:in `current_version' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:652:in `block in migrate' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:652:in `each' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:652:in `detect' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:652:in `migrate' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:545:in `up' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/migration.rb:526:in `migrate' .rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.1.0.rc5/lib/active_record/railties/databases.rake:161:in `block (2 levels) in <top (required)>' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:205:in `call' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:205:in `block in execute' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:200:in `each' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:200:in `execute' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain' .rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/task.rb:144:in `invoke' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:112:in `invoke_task' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:90:in `block (2 levels) in top_level' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:90:in `each' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:90:in `block in top_level' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:84:in `top_level' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:62:in `block in run' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/lib/rake/application.rb:59:in `run' .rvm/gems/ruby-1.9.2-p180/gems/rake-0.9.2/bin/rake:32:in `<top (required)>' .rvm/gems/ruby-1.9.2-p180/bin/rake:19:in `load' .rvm/gems/ruby-1.9.2-p180/bin/rake:19:in `<main>' Tasks: TOP => db:migrate