Ruby on Rails-對有向圖建模

Question

我正在嘗試為我的Rails應用程序上的紅寶石建模一個有向圖，我有兩個模型，標記和連接

class Connection < ActiveRecord::Base
  attr_accessible :cost, :from_id, :to_id
  belongs_to :from_tag, :foreign_key => "from_id", :class_name => "Tag" 
  belongs_to :to_tag, :foreign_key => "to_id",   :class_name => "Tag" 
  end



class Tag < ActiveRecord::Base
  attr_accessible :location_info, :reference
  has_many :to_connections, :foreign_key => 'from_id', :class_name => 'Connection' 
  has_many :to_tags, :through => :to_connections  
  has_many :from_connections, :foreign_key => 'to_id', :class_name => 'Connection' 
  has_many :from_tags, :through => :from_connections
  end

當我像這樣創建標簽時

a = Tag.create(:reference => "a", :location_info => "Tag A")
b = Tag.create(:reference => "b", :location_info => "Tag B")

工作正常。

但是當我試圖在兩者之間建立聯系時

Connection.create(:from_tag => a, :to_tag => b, :cost => 5)

我說錯了

“ ActiveModel :: MassAssignmentSecurity :: Error：無法大量分配受保護的屬性：from_tag和to_tag”

，有人可以看到問題嗎？

Answer 1

您無法大規模分配關系。

http://api.rubyonrails.org/classes/ActiveModel/MassAssignmentSecurity/ClassMethods.html

connection = Connection.new
connection.from_tag = a
connection.to_tag = b
connection.cost = 5
connection.save