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Ruby on rails ActiveRecord：集合与lt&书信电报；对象和关联=（关联）

ruby-on-rails

Ruby on rails ActiveRecord：集合与lt&书信电报；对象和关联=（关联）,ruby-on-rails,associations,has-many,belongs-to,rails-activerecord,Ruby On Rails,Associations,Has Many,Belongs To,Rails Activerecord,让我们举一个例子： class Subscription < ActiveRecord::Base belongs_to :user end class User < ActiveRecord::Base has_many :subscriptions end u1 =User.new s1 = Subscription.new 类订阅

让我们举一个例子：

class Subscription < ActiveRecord::Base
 belongs_to :user
end

class User < ActiveRecord::Base
 has_many :subscriptions
end

u1 =User.new
s1 = Subscription.new

类订阅
根据我的说法，以下两行应该是等效的：

u1.subscriptions << s1, and 
s1.user = u1

u1.0订阅

它给出了u2
它将在保存s1后建立该关联。对于u1.subscriptions分配，您正在处理内部分配的结果（也未保存）。如果您想查看等效的内容，请在分配后查看s1.user\u id。

u1.subscriptions << s1
[s1]

u1.subscriptions << s2
[s1,s2]



s1.user = u2