Rails 模型和 ActiveRecord 中的子类化
我正在编写一个电子商务类型的网络应用程序（不完全是，但给你一个想法）。我将展示不同类型的产品，这些产品彼此之间没有什么关系，但我希望有一个 Product 父类，以便对所有子类有一个共同的视图，并共享一些字段和行为。
但这给我带来了很多问题，特别是关于 ActiveModel：产品不应该有自己的表，但我希望其子类（酒店、餐厅等）中的某些字段从中继承这些字段。我该怎么办呢？
拥有 Product 父类的另一个原因是，最终我将需要使用 Product.all 和类对象的不同范围。
也许我完全被误导了，所以请随意建议任何方法来做到这一点。也许使用模块？
I am programming an e-commerce type web app (not exactly, but to give you an idea). I will be displaying different types of products that have little to do with one another, but I would like to have a Product parent class, to have a common view for all the subclasses, and share some fields and behaviours.
But this raises many questions to me, specially regarding to ActiveModel: Product shouldnt have its own table, but I would want some fields in its subclasses (hotel, restaurant, etc) to inherit those fields from it. How would I go about that?
Another reason to have a Product parent class would be that eventually I will need to use Product.all and different scopes of the class objects.
Maybe I am totally misguided, so feel free to suggest any way to do this. Maybe using a module?
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首先，继承意味着字段是继承的；因此，您不只是获取子类中父类的某些字段，而是获取父类的所有字段。
您可以通过多种方式实现您想要的目标：
set_table_name来路由模型以使用另一个表。如果您有多个表与product表共享相同的字段，这非常有用。product_type之类的属性来区分，您可以使用default_scope始终应用诸如default_scope 其中的条件(:product_type => :hotel)使用 API 作为上述使用的参考方法。
First, inheritance implies that fields are inherited; therefore, you don't just a get some fields you get all the fields for the parent class in the subclass.
You can achieve what you want in multiple ways:
set_table_namein the subclass to route the model to use another table. This is useful if you have multiple tables that share the same fields as yourproducttable.product_typeyou can usedefault_scopeto always apply a condition such asdefault_scope where(:product_type => :hotel)Use the API as a reference for the use of the aforementioned methods.