Rails的belongs_to的关联(含:将class_name)返回nil [英] Rails belongs_to association (with :class_name) returns nil
本文介绍了Rails的belongs_to的关联(含:将class_name)返回nil的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我是比较新的Rails开发,我有一个小团体问题。我想的名字比它链接到模型中的不同关联的东西。
I'm relatively new to Rails development and I'm having a minor associations problem. I'd like to name an association something different than the model it's linked to.
我有以下2种型号:
class User < ActiveRecord::Base
has_many :events
end
class Event < ActiveRecord::Base
belongs_to :admin, :class_name => "User" # So we can call event.admin to retrieve the User who owns this Event
end
我建一个用户,如下所示:
I build a User as follows:
event = event.create! :title => "New Event"
user = User.create! :username => "thinkswan"
user.events << event
user.save
当我跳进我收到以下控制台:
When I hop into the console I receive the following:
irb> user = User.find(1)
irb> user.events
=> [#<Event id: 1, title: "New Event", user_id: 1, created_at: "2011-06-09 06:41:09", updated_at: "2011-06-09 06:41:10">]
irb> event = Event.find(1)
irb> event.user_id
=> 1
irb> event.admin
=> nil
任何人都可以解释为什么管理
的关联没有返回用户它的指向?谢谢!
Can anyone explain why the admin
association isn't returning the User it's pointing to? Thanks!
推荐答案
您需要同时指定:将class_name
和:foreign_key
,例如:
You need to specify both :class_name
and :foreign_key
, for example:
belongs_to :admin, :class_name => "User", :foreign_key => "user_id"
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