Rails模型继承

Question

如果我有一个用户并且我想要制作不同类型的用户，比如说只有一个电子邮件的普通用户和拥有网站字段的订阅者，我如何让订阅者继承来自只有添加字段的用户的所有内容？

Answer 1

You would need to create a table with all of the fields, as well as specify a type column. ie

create_table :users do |t|
  t.string :email
  t.string :website
  t.string :type
end

Then you can have classes like

Class User < ActiveRecord::Base

Class Subscriber < User

A subscriber will inherit everything from the Users model. The type column is there so that you can distinguish from the different models. For instance using

Subscriber.all 

Will only get subscribers, where as if you did not use the 'type' column it would also find users too.

Answer 2

You want single table inheritance , described at the link by Alex Reisner. STI uses a single table to represent multiple models that inherit from a base model. In the Rails world, the database schema has a column which specifies the type of model represented by the row. Adding a column named type in a database migration has Rails infer the table uses STI, although the column can be an arbitrary name if you specify the name in the data model (see the class method 'inheritance_column' ). Note that this makes type a reserved word.