Question

如果我有一个继承自另一个模型的模型，则不会继承关系。这似乎是有意的，但为了我的目的，我想继承这种关系。继承活跃记录关系的最佳方式是什么？

e.g。

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

使用Rails 4.2.4测试您的示例我发现实际的关系是继承的。

class Address < ActiveRecord::Base
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :addresses
end

class OriginalUser < User
end

在rails控制台中：

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">]>

Rails：允许子类继承关系

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