继承类型之间的 STI 变化. [英] STI change amongs inherited types.

问题描述

在我的模型中，我像这样使用 STI

In my models I use STI like this

车辆型号:vehicle.rb

Vehicle Model: vehicle.rb

class Vehicle < ActiveRecord::Base
end

车型:car.rb

class Car < Vehicle
end

总线型号:bus.rb

Bus Model: bus.rb

class Bus < Vehicle
end

如果我创建了一辆汽车，我可以以某种方式将其类型更改为车辆或巴士吗?

If I create a Car can I somehow change it's type to Vehicle or Bus?

推荐答案

要永久更改类型，请更改 type 列的值.

To permanently alter the type, change the value of the type column.

c1 = Car.first
c1.name # BMW

c1.update_attribute(:type, "Bus")

b1 = Bus.first
b1.name # BMW

要在不从数据库重新加载的情况下更改内存中的对象类型，请使用becomes, as in

To also change the object type in-memory without reloading it from the DB, use "becomes, as in

c1 = c1.becomes(Bus)

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