学习札记――关联表双外键实现及factory_girl构建关联表新学习的语法

 我们项目需求要关联表具有两个外键的功能，其实语法很简单代码如下

class SubscriptionRecord < ActiveRecord::Base
 belongs_to :sender,
             :class_name => 'User',
             :foreign_key => 'sender_id'
  belongs_to :receiver,
             :class_name => 'User',
             :foreign_key => 'receiver_id'
end

class User < ActiveRecord::Base
 has_many :receivers,
           :class_name => "SubscriptionRecord",
           :foreign_key => "receiver_id"


  has_many :senders,
           :class_name => "SubscriptionRecord",
           :foreign_key => "sender_id"
end

语法并不是很难，关键在于

has_many :receivers,
           :class_name => "SubscriptionRecord",

:class_name  = >  "SubscriptionRecord",  注意要写大写不可用小写加下划线的方式代替。

而下面在说说一个新语法构建factory_girl的测试用例

代码如下

 

factory :user_with_senders, :class => :user do

     ignore do
       sample_size 5
     end
     after_create do |user, evaluator|
       FactoryGirl.create_list(:subscription_record, evaluator.sample_size, sender: user)
     end
   end

   factory :user_with_metadata, :class => :user do

     ignore do
       sample_size 5
     end
     after_create do |user, evaluator|
       FactoryGirl.create_list(:metadatum, evaluator.sample_size, user: user)
     end

   end

主要是用了FactoryGirl.create_list 这个语法主要用处在于可以批量构建需要的关联表创建

语法FactoryGirl.create_list(:metadatum, evaluator.sample_size, user: user)  

如上 第一个是创建的factory用列，而一个是创建的个数，第三个是属性值，也就是belong_to定义额外键。