Question

我正在尝试为rails应用程序上的ruby建模有向图我有两个模型，标签和连接

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

当我创建这样的标签时

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

工作正常。

但是当我尝试在两者之间建立联系时

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

我收到错误说

“ActiveModel :: MassAssignmentSecurity :: Error：无法批量分配受保护的属性： from_tag和to_tag“

，有人能看到问题吗？

Answer 1

你无法大规模分配关系。

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

Ruby on Rails - 为有向图建模

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