Ruby on rails ve_支持/通知。rb:123:in“instrument” actionpack（3.2.1）lib/action\u controller/metal/instrumentation.rb:29:in'process\u action' actionpack（3.2.1）lib/action_controller/metal/params_wrapper.rb:205:在“过程_动作”中 activerecord（3.2.1）lib/active\u record/railties/controller\u runtime.rb:18:in'process\u action' actionpack（3.2.1）lib/abstract_controller/base.rb:121:正在进行中 actionpack（3.2.1）lib/abstract_controller/rendering.rb:45:in'process' actionpack（3.2.1）lib/action_controller/metal.rb:203:in'dispatch' actionpack（3.2.1）lib/action\u controller/metal/rack\u delegation.rb:14:in'dispatch' actionpack（3.2.1）lib/action_controller/metal.rb:246:in“block in action” actionpack（3.2.1）lib/action\u dispatch/routing/route\u set.rb:66:in'call' actionpack（3.2.1）lib/action_dispatch/routing/route_set.rb:66:in'dispatch' actionpack（3.2.1）lib/action\u dispatch/routing/route\u set.rb:30:in'call' 旅程（1.0.3）lib/travely/router.rb:68:in“呼叫阻塞” 旅程（1.0.3）lib/tourney/router.rb:56:in'each' 旅程（1.0.3）lib/travely/router.rb:56:in'call' actionpack（3.2.1）lib/action\u dispatch/routing/route\u set.rb:589:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/best\u standards\u support.rb:17:in'call' 机架（1.4.1）lib/rack/etag.rb:23:in'call' rack（1.4.1）lib/rack/conditionalget.rb:25:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/head.rb:14:in'call' actionpack（3.2.1）lib/action_dispatch/middleware/params_parser.rb:21:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/flash.rb:242:in'call' 框架（1.4.1）lib/rack/session/abstract/id.rb:205:在“上下文”中 机架（1.4.1）lib/rack/session/abstract/id.rb:200:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/cookies.rb:338:in'call' activerecord（3.2.1）lib/active\u record/query\u cache.rb:64:in'call' activerecord（3.2.1）lib/active\u record/connection\u adapters/abstract/connection\u pool.rb:443:in'call' actionpack（3.2.1）lib/action_dispatch/middleware/callbacks.rb:28:in'block in call' activesupport（3.2.1）lib/active\u support/callbacks.rb:405:in`_run\u 539745845193235082\u call\u 2953064504705011211\u callbacks' activesupport（3.2.1）lib/active\u support/callbacks.rb:405:in`\uu run\u callback' activesupport（3.2.1）lib/active\u-support/callbacks.rb:385:in`_-run\u-call\u-callbacks' activesupport（3.2.1）lib/active\u support/callbacks.rb:81:in'run\u callbacks' actionpack（3.2.1）lib/action_dispatch/middleware/callbacks.rb:27:in'call' actionpack（3.2.1）lib/action_dispatch/middleware/reloader.rb:65:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/remote\u ip.rb:31:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/debug\u exceptions.rb:16:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/show\u exceptions.rb:56:in'call' railties（3.2.1）lib/rails/rack/logger.rb:26:in'call_app' railties（3.2.1）lib/rails/rack/logger.rb:16:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/request\u id.rb:22:in'call' rack（1.4.1）lib/rack/methodoverride.rb:21:in'call' rack（1.4.1）lib/rack/runtime.rb:17:in'call' activesupport（3.2.1）lib/active\u support/cache/strategy/local\u cache.rb:72:in'call' 机架（1.4.1）lib/rack/lock.rb:15:in'call' actionpack（3.2.1）lib/action\u dispatch/middleware/static.rb:53:in'call' railties（3.2.1）lib/rails/engine.rb:479:in'call' railties（3.2.1）lib/rails/application.rb:220:in'call' 机架（1.4.1）lib/rack/content_length.rb:14:in'call' railties（3.2.1）lib/rails/rack/log_tailer.rb:14:in'call' rack（1.4.1）lib/rack/handler/webrick.rb:59:in'service' /Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/httpserver.rb:111:在“服务”中 /Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/httpserver.rb:70:in'run' /Users/AM/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/server.rb:183:in'block in start_thread'

应用程序的模型是名为business.rb的文件，它包含以下内容：

class Business < ActiveRecord::Base
  establish_connection "Listings_development"
end

class业务

由于您的表似乎没有主键，请先读后写，将

id

列添加到表中

def change
  add_column :business, :id, :primary_key
end

---

如上所述，如果对象尚未持久化，它将返回

nil

这是因为指向不在数据库中的对象的链接实际上是一个断开的链接。在尝试链接到对象之前，请确保对象已保存

---

这可能就是问题所在，不是模特。使用辅助对象获取引用对象的辅助对象：

<td><%= link_to 'Show', business_path(business) %></td>

我想这里也会出现同样的问题：

<td><%= link_to 'Destroy', user, ... %></td>

应将该行替换为：

<td><%= link_to 'Destroy', destroy_user_path(user), ... %></td>

不，这似乎不是问题所在problem@banditKing，你能发布完整的调用堆栈吗？@banditKing:请不要编辑其他人的答案来添加调用堆栈。请编辑您的问题并将其添加到那里。您实际上可以将

link\u传递到

模型对象。甚至还有一个你链接的

：）

。所以我发现问题可能与这篇文章有点类似：我现在正试图解决它…你是否在你的模型中覆盖

到_key

？

business.to_key

返回什么？如果您可以发布

business

：）@summa该业务的模型代码已添加到post@AndrewMarshall我还没有覆盖business.to_key方法。我刚刚测试了该方法的输出，它是空的。

def change
  add_column :business, :id, :primary_key
end

<td><%= link_to 'Show', business %></td>

<td><%= link_to 'Show', business_path(business) %></td>

<td><%= link_to 'Destroy', user, ... %></td>

<td><%= link_to 'Destroy', destroy_user_path(user), ... %></td>