带有 .new 的 Rails 控制台出错答案

【问题标题】：Error from rails console with .new带有 .new 的 Rails 控制台出错
【发布时间】：2011-11-09 20:29:49
【问题描述】：

这是 rails 生产控制台中的错误消息。用户是一个模型，错误是由“a = User.new”创建的。

D:\rails_proj\emclab-failed>rails c production
Loading production environment (Rails 3.1.0)
irb(main):001:0> a = User.new
  ←[1m←[36m (0.0ms)←[0m  ←[1mSHOW TABLES←[0m
  ←[1m←[35m (10.0ms)←[0m  describe `users`
SyntaxError: C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/read.rb:91: syntax error, unexpected keyword_end
C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/read.rb:93: syntax error, unexpected $end, expecting keyword_end
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/read.rb:83:in `module_eval'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/read.rb:83:in `define_read_method'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/read.rb:42:in `define_method_attribute'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/time_zone_conversion.rb:35:in `define_method_attribute'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activemodel-3.1.0/lib/active_model/attribute_methods.rb:291:in `block in define_attribute_method'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activemodel-3.1.0/lib/active_model/attribute_methods.rb:286:in `each'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activemodel-3.1.0/lib/active_model/attribute_methods.rb:286:in `define_attribute_method'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activemodel-3.1.0/lib/active_model/attribute_methods.rb:282:in `block in define_attribute_methods'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activemodel-3.1.0/lib/active_model/attribute_methods.rb:282:in `each'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activemodel-3.1.0/lib/active_model/attribute_methods.rb:282:in `define_attribute_methods'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods.rb:14:in `define_attribute_methods'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods.rb:65:in `respond_to?'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/attribute_methods/read.rb:103:in `read_attribute'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/base.rb:1774:in `attribute_for_inspect'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/base.rb:1891:in `block in inspect'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/base.rb:1889:in `collect'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/base.rb:1889:in `inspect'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.1.0/lib/rails/commands/console.rb:45:in `start'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.1.0/lib/rails/commands/console.rb:8:in `start'
        from C:/Ruby192/lib/ruby/gems/1.9.1/gems/railties-3.1.0/lib/rails/commands.rb:40:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'irb(main):002:0>

但是，开发中的相同命令会生成一个没有任何错误的新实例。不同之处在于生产数据库中没有数据。它是用于开发的 sqlite3 和用于生产的 mysql 5.1.54。

Loading development environment (Rails 3.1.0)
irb(main):001:0> a = User.new
=> #<User id: nil, name: nil, email: nil, encrypted_password: nil, salt: nil, status: "active", created_at: nil, updated_at: nil, user_type: nil>

有什么想法吗？谢谢。

【问题讨论】：

你能分享你的 read.rb 代码吗？
错误发生在 describe 或 'new' 上吗？
它是新的。见附上的错误。 read.rb 是 rails 的一部分。

标签： mysql ruby-on-rails sqlite ruby-on-rails-3.1

【解决方案1】：

你用什么 gem 来做 mysql？根据this issue，如果您使用的是mysql2 gem，您可能只需要运行bundle update mysql2。

【讨论】：

所以你仍然得到同样的错误？如果是这样，1）你的意思是接受这个答案是正确的吗？ 2）当你运行'bundle update'时，它是否更新了mysql2版本？