nil的未定义方法`eq’：nilClass with rails 3和ruby enterprise on ubuntu hardy
我不确定是什么原因导致这个错误但是因为我在乘客中遇到了这个问题而现在在控制台中我也在想，也许mysql驱动程序是问题所在？ 在osx / 10.6上，一切都按预期工作。 它只是不会在Ubuntu 8.04上耐用。
我把问题钉在了“destroy”方法上，或者当我直接调用activerecord实例的方法时。 为什么会这样？ 有任何想法吗？
系统：
- Ubuntu 8.04耐用。
- ruby 1.8.7（2010-04-19 patchlevel 253）[i686-linux]，MBARI 0x8770，Ruby Enterprise Edition 2010.02
- rails 3.0.0-beta4
- mysql Ver 14.12 Distrib 5.0.51a，debian-linux-gnu（i486）使用readline 5.2
这是错误输出
root@gehege:/var/www/foobar.com/api.foobar.com/v1# rake cleanup:status_cleanup RAILS_ENV=production --trace (in /var/www/foobar.com/api.foobar.com/v1) ** Invoke cleanup:status_cleanup (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute cleanup:status_cleanup rake aborted! undefined method `eq' for nil:NilClass /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/persistence.rb:76:in `destroy' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/locking/optimistic.rb:110:in `destroy' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/callbacks.rb:278:in `destroy' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activesupport-3.0.0.beta4/lib/active_support/callbacks.rb:412:in `_run_destroy_callbacks' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/callbacks.rb:278:in `destroy' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/transactions.rb:230:in `destroy' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/transactions.rb:287:in `with_transaction_returning_status' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in `transaction' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/transactions.rb:202:in `transaction' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/transactions.rb:285:in `with_transaction_returning_status' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/activerecord-3.0.0.beta4/lib/active_record/transactions.rb:230:in `destroy' /var/www/foobar.com/api.foobar.com/v1/lib/tasks/cleanup.rake:8 /var/www/foobar.com/api.foobar.com/v1/lib/tasks/cleanup.rake:6:in `each' /var/www/foobar.com/api.foobar.com/v1/lib/tasks/cleanup.rake:6 /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/1.8/monitor.rb:242:in `synchronize' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' /opt/ruby-enterprise-1.8.7-2010.02/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 /opt/ree/bin/rake:19:in `load' /opt/ree/bin/rake:19 编辑：
即使在运行apt-get更新/升级到最新的hardy软件包并重新编译ree和mysql gem之后我也会遇到同样的错误。
回答我自己的问题：经过一些研究后我发现rails（activerecord）需要映射到模型的表上的id字段。 如果您使用链接表，则不需要它们 – 但对于您希望作为模型进行地址的表格，它们是。 在我的情况下，解决方案是添加
set_primary_key :cal_id
其中cal_id是我唯一的密钥。
从没有id字段的表中删除时我有同样的错误。 我认为这是一个Rails 3 beta 4错误。
在将没有id的HABTM表转换为has_many：through的连接模型后，我发现了这个问题。 我忘了添加：id列…