Rails：允许子类继承关系

Question

如果我有一个从另一个模型继承的模型，则关系不会被继承。这似乎是故意的，但为了我的目的，我想继承关系。继承活动记录关系的最佳方式是什么？

例如

class User 
    has_many :addresses 
end 

class OriginalUser < User 
    default_scope where('created_at <= ', DateTime.now - 5.years) 

    # how can I inherit the has_many :addresses relationship? 
end 

Answer 1

测试您例如使用Rails 4.2.4我发现的关系实际上是继承。

class Address < ActiveRecord::Base 
    belongs_to :user 
end 

class User < ActiveRecord::Base 
    has_many :addresses 
end 

class OriginalUser < User 
end 

在导轨控制台：

2.2.3 :001 > user = User.create({name: 'Martin'}) 
2.2.3 :002 > address = Address.create({city: 'Berlin'}) 
2.2.3 :003 > user.addresses << address 
2.2.3 :004 > address.user 
=> #<User id: 1, name: "Martin", created_at: "2015-10-09 18:15:17", updated_at: "2015-10-09 18:15:17"> 

2.2.3 :005 > original_user = OriginalUser.create({name: 'Steel'}) 
2.2.3 :006 > another_address = Address.create({city: 'Boulder'}) 
2.2.3 :007 > original_user.addresses << another_address 
2.2.3 :008 > another_address.user 
=> #<OriginalUser id: 2, name: "Steel", created_at: "2015-10-09 18:20:58", updated_at: "2015-10-09 18:20:58"> 
2.2.3 :009 > original_user.addresses 
=> #<ActiveRecord::Associations::CollectionProxy [#<Address id: 2, city: "Boulder", user_id: 2, created_at: "2015-10-09 18:22:14", updated_at: "2015-10-09 18:22:48">]>