在Rails的多发性关系，其中的类名不匹配协会名称 [英] Multipe relationships in Rails where the class name does not match the association name

问题描述

我有涉及到两个用户私人信息的模式，我怎么建立一个协会，使PM.sender是发件人的用户模型和PM.receiver是收件人的用户模式？ （这样我可以叫PM.sender.username等。）

I have a private message model that relates to two users, how do I setup an association so that PM.sender is the sender's user model and PM.receiver is recipient's user model? (so that I can call PM.sender.username etc.)

我有一个sender_id和receiver_id领域。

I have a sender_id and receiver_id field.

推荐答案

假设模型类消息和用户，在消息型号：

Assuming model classes Message and User, in your Message model:

class Message < ActiveRecord::Base
  belongs_to :sender, :class_name => 'User'
  belongs_to :receiver, :class_name => 'User'
end

由于类的名字不能推导出明确的的关联名称：将class_name 要求

Because the class name can't be deduced from the association name the explicit :class_name is required.

更新：刚走选中，：不应该，只要外键的名称是名称需要foreign_key 参数该协会随后 _id ，它是在这种情况下。

Update: Having just checked, the :foreign_key parameter shouldn't be required as long as the name of the foreign key is the name of the association followed by _id, which it is in this case.

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