Ruby on rails 3 从rails 3.0.0升级到3.0.11后出现Activerecord错误-表不存在

我从rails 3.0.0升级到3.0.11，但出于各种原因，我还不想升级到3.1

我在文件中更改了以下内容：

-gem 'rails', '3.0.0'
-gem 'mysql2', "0.2.6"
+gem 'rails', '3.0.11'
+gem 'mysql2', "~>0.2.7"

启动控制台并尝试：

 PopularMedia.where(:media_type => 1).all

得到这个：

 ActiveRecord::StatementInvalid: Mysql2::Error: Table 'matcha_development.popular_media' doesn't exist: SELECT `popular_media`.* FROM `popular_media` WHERE `popular_media`.`id` = 1
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/mysql2-0.2.18/lib/active_record/connection_adapters/mysql2_adapter.rb:265:in `query'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/mysql2-0.2.18/lib/active_record/connection_adapters/mysql2_adapter.rb:265:in `block in execute'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/connection_adapters/abstract_adapter.rb:202:in `block in log'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.0.11/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/connection_adapters/abstract_adapter.rb:200:in `log'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/mysql2-0.2.18/lib/active_record/connection_adapters/mysql2_adapter.rb:265:in `execute'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/mysql2-0.2.18/lib/active_record/connection_adapters/mysql2_adapter.rb:586:in `select'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/connection_adapters/abstract/query_cache.rb:56:in `select_all'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/base.rb:473:in `find_by_sql'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/relation.rb:64:in `to_a'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/relation/finder_methods.rb:143:in `all'
from (irb):2
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/railties-3.0.11/lib/rails/commands/console.rb:44:in `start'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/railties-3.0.11/lib/rails/commands/console.rb:8:in `start'
from /usr/local/rvm/gems/ruby-1.9.2-p290/gems/railties-3.0.11/lib/rails/commands.rb:23:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'

---

以前工作得很好，那么可能是什么问题呢？

当我遇到这样的问题时，我通常会使用更新的rails gem创建一个新项目。这样，我可以查看生成的GEM文件，并将其与我拥有的旧文件进行比较，然后继续相应地更新它

另外，确保在更改文件中的任何内容后运行bundle安装

如果你忘记了，这通常是你有问题的原因

我希望这能帮助你解决问题