带有多个foreign_keys的Rails模型has_many [英] Rails Model has_many with multiple foreign_keys

问题描述

相对于Rails而言，它相对较新，并且尝试使用具有名称，性别，father_id和mother_id(2个父母)的单个Person模型对非常简单的家庭树"进行建模.下面基本上是我想做的，但是显然我不能在has_many中重复:children(第一个被覆盖).

Relatively new to rails and trying to model a very simple family "tree" with a single Person model that has a name, gender, father_id and mother_id (2 parents). Below is basically what I want to do, but obviously I can't repeat the :children in a has_many (the first gets overwritten).

class Person < ActiveRecord::Base
  belongs_to :father, :class_name => 'Person'
  belongs_to :mother, :class_name => 'Person'
  has_many :children, :class_name => 'Person', :foreign_key => 'mother_id'
  has_many :children, :class_name => 'Person', :foreign_key => 'father_id'
end

是否有一种简单的方法可以将has_many与2个外键一起使用，或者根据对象的性别更改外键?还是完全有另一种/更好的方式?

Is there a simple way to use has_many with 2 foreign keys, or maybe change the foreign key based on the object's gender? Or is there another/better way altogether?

谢谢！

推荐答案

在IRC上找到了一个似乎可行的简单答案(感谢Radar):

Found a simple answer on IRC that seems to work (thanks to Radar):

class Person < ActiveRecord::Base
  belongs_to :father, :class_name => 'Person'
  belongs_to :mother, :class_name => 'Person'
  has_many :children_of_father, :class_name => 'Person', :foreign_key => 'father_id'
  has_many :children_of_mother, :class_name => 'Person', :foreign_key => 'mother_id'
  def children
     children_of_mother + children_of_father
  end
end

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