设计一个 Rails 应用程序:单表继承? [英] Designing a Rails application: single table inheritance?

问题描述

我已经研究了几天了，我知道有很多文章讨论单表继承和与 Rails 的多态关联.很多有用的材料来自 2009 年或更早，我想知道现在是否有更好的方法来解决这个问题.

I've been researching this for a few days now, and I know there is an abundance of articles that talk about single table inheritance and polymorphic associations with Rails. A lot of helpful material is from 2009 or before and I'm wondering if there is a better approach to this problem now.

该应用程序有几种不同的用户类型(即买方和卖方)，每种类型都有一个个人资料.每种用户类型的个人资料确实不同，因此我目前排除了使用一个通用个人资料"表的想法.

The application has a couple of different user types (ie, Buyer and Seller), each of which have a profile. The profile for each user type is really different, so I'm currently ruling out the idea of one generic "profile" table.

这与这个解决方案相同.

class User < ActiveRecord::Base
  # authentication stuff
end

class UserType1 < User
  has_one :user_type_1_profile
end

class UserType2 < User
  has_one :user_type_2_profile
end

...

class UserTypeN < User
  has_one :user_type_n_profile
end

根据我的研究，这是一种混合模型"设计.

Based on my research, this is kind of a "mixed model" design.

老实说，在这一点上，我不知道任何其他可行的解决方案.每次我看到类似问题问我看到提出了多态关联的想法.有人可以详细说明多态关联在这种情况下如何工作吗?

Honestly, at this point I don't know of any other solution that would work. Every time I've seen similar questions asked I see the idea of polymorphic associations brought up. Could someone elaborate how a polymorphic association would work in this case?

有人有其他设计建议吗?

Does anyone have any other design suggestions?

推荐答案

在此处使用具有各种配置文件类型的多态关联会更好.

You would be better off with a polymorphic association here with various profile types.

class User < ActiveRecord::Base
  belongs_to :profile, :polymorphic => true
end

class ProfileTypeA < ActiveRecord::Base
  has_one :user, :as => :profile
end

class ProfileTypeB < ActiveRecord::Base
  has_one :user, :as => :profile
end

这需要你有一个这样的迁移/表:

Which would require you have a migration/table like this:

change_table :users do |t|
  t.integer :profile_id
  t.string :profile_type
  # OR (same thing, the above is more explicit)
  t.references :profile, :polymorphic => true
end

指南中有更多相关信息:http://guides.rubyonrails.org/association_basics.html#polymorphic-associations

There's more info on this in the Guide: http://guides.rubyonrails.org/association_basics.html#polymorphic-associations

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