Question

我需要一种将2个不同对象引用为1的方法。

我有一个Message对象，需要跟踪收件人。问题是收件人可以是用户还是联系人。

模型应该是：？

class Message < ActiveRecord::Base
  has_many :users, as: :recipients
  has_many :contacts, as: :recipients
end

class User < ActiveRecord::Base
  belongs_to :recipient, polymorphic: true
end

class User < ActiveRecord::Base
  belongs_to :recipient, polymorphic: true
end

因为，我觉得多态关系是以相反的方式构建的。

另外，这种方式不允许我引用我所需要的@ message.recipients。

我希望这是有道理的谢谢

Answer 1

What you have done is completely incorrect. I think you need many-to-many association. My association whould be that:

class Message < ActiveRecord::Base
  has_many :recipient_links
  has_many :users, through: :recipient_links, source: :recipient, source_type: 'User'
  has_many :contacts, through: :recipient_links, source: :recipient, source_type: 'Contact'
end

class Contact < ActiveRecord::Base
  has_many :recipient_links, as: :recipient
  has_many :messages, through: :recipient_links
end

class User < ActiveRecord::Base
  has_many :recipient_links, as: :recipient
  has_many :messages, through: :recipient_links
end

# fields: message_id, recipient_id, recipient_type
class RecipientLink < ActiveRecord::Base
  belongs_to :recipient, polymorphic: true
  belongs_to :message
end

Answer 2

...我还无法添加评论，所以我在这里给出了解决方案：当使用来自up的答案时，只接收2个请求中的所有@ message.recipients：

RecipientLink.includes(:recipient).where(message_id: @message.id).collect(&:recipient)

has_many（不同的对象）as：一种对象

2 个答案: