Activerecord has_many：通过多个模型 [英] Activerecord has_many :through through multiple models

问题描述

我正在尝试使用 user.comments 访问给定用户的所有评论。该查询将通过两个不同的模型，这两个模型都可能返回结果。我的关系设置如下：

I'm trying to access all comments from a given user with user.comments. The query is to go through two different models, which likely both return results. My relations are set up as follow:

class User < ActiveRecord::Base
  has_many :organisers
  has_many :participants
  has_many :comments, through: :participants / :organisers (see explenation below)
end

class Organiser < ActiveRecord::Base
  belongs_to :user
end

class Participant  < ActiveRecord::Base
  belongs_to :user
end

class Comment < ActiveRecord::Base
  belongs_to :organiser
  belongs_to :participant
end

已确认评论属于参与者或组织者。

A comment is validated to belong to either a participant, or an organiser.

我不确定该如何处理。我已经尝试过

I'm not sure how to go about this. I've tried

has_many :comments, through: :participants
has_many :comments, through: :organisers

和

has_many :comments, through: [:organisers, :participants]

但是最后一个是吨轨。有适当的方法来做到这一点吗？谢谢！

But that last one isn't rails. Is there a proper way to do this? Thanks!

推荐答案

您能做些简单的事情吗：

Could you do something as simple as:

has_many :comments, -> { joins(:participant, :organizer) }, class_name: 'Comment'

此 返回所有具有参与者或组织者用户的评论，因为Rails倾向于默认 joins 为内部联接。您甚至可能不需要：class_name 自变量。

This should return all comments that have a Participant or Organizer User, since Rails tends to default joins to an inner join. You may not even need that :class_name argument.

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