活动记录-多次连接同一表

也许这样的事情能奏效?(我还没有测试代码)

class User < ApplicationRecord
  has_many :doctors
  has_many :patients, through: :doctors
end

class Doctor < ApplicationRecord
  belongs_to :user
  has_many :patients
end

class Patient < ApplicationRecord
  belongs_to :doctor
  belongs_to :user
end

Patient.joins(user: {doctors: :user}).where("patient.name = 'some condition' or doctor.name='some other condition'")

可以创建名为 Patient 和 Doctor 继承自 User ,然后将用户称为患者和医生,而不是一般用户。

class Doctor < User
  has_many :a
end
class Patient < User
  has_many :b
end

这是单表继承: https://api.rubyonrails.org/classes/ActiveRecord/Inheritance.html