Rails ActiveRecord 模型 has_one 两次到具有不同外键的同一模型 [英] Rails ActiveRecord model has_one twice to the same model with different foreign keys

问题描述

我的模型 Offer 有很多字段，其中有两个字段与同一个模型相关:

I have model Offer with many fields, among which are there are two fields that relate to the same model:

# == Schema Information
#
# Table name: offers
#
#  id                   :integer          not null, primary key
#  name                 :string(250)      default(""), not null
#  destination_id       :integer          not null
#  cruise_line_id       :integer          not null
#  ship_id              :integer          not null
#  departure_date       :date             not null
#  departure_port_id    :integer
#  arrival_date         :date             not null
#  arrival_port_id      :integer

departure_port_id 和arrival_port_id 属于同一个型号Port，但也可以是NULL，如果没有出发或提供到达港口.

departure_port_id and arrival_port_id relate to the same model Port, but can be also NULL, if no departure or arrival port provided.

Offer 和 Port 模型在这种情况下应该是什么样子的?

How should Offer and Port models look like in this case?

推荐答案

是这样的:

class Offer < ActiveRecord::Base
  belongs_to :departure_port, class_name: "Port", foreign_key: "departure_port_id"
  belongs_to :arrival_port, class_name: "Port", foreign_key: "arrival_port_id"
end

class Port < ActiveRecord::Base
  has_one :offer
end

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