試圖在軌兩個人之間的關係模型

Question

我有以下兩個簡單的類：

class Person < ActiveRecord::Base 
    has_many :parent_child_assignments 

    has_many :children, :through => :parent_child_assignments 
    has_many :parents, :through => :parent_child_assignments 
end 

class ParentChildAssignment < ActiveRecord::Base 
    belongs_to :parent, :class_name => "Person" 
    belongs_to :child, :class_name => "Person" 
end 

從下面的軌道創建命令

rails generate model Person name:string 
rails generate model ParentChildAssignment parent_id:integer child_id:integer 

我可以得到一個方向（joe.children或joe.parents）工作，但不能同時工作

有人必須問過這個問題，但我找不到它。

在此先感謝。

Answer 1

的類應該是這樣的：

class Person < ActiveRecord::Base 
    has_many :parent_child_assignments_as_parent, class_name: 'ParentChildAssignment', :foreign_key => :parent_id 
    has_many :parent_child_assignments_as_child, class_name: 'ParentChildAssignment', :foreign_key => :child_id 

    has_many :children, :through => :parent_child_assignments_as_parent 
    has_many :parents, :through => :parent_child_assignments_as_child 
end 

class ParentChildAssignment < ActiveRecord::Base 
    belongs_to :parent, :class_name => "Person", :foreign_key => :parent_id 
    belongs_to :child, :class_name => "Person", :foreign_key => :child_id 
end