Rails属于多个属性中的相同模型

There is a model called Student and has an attribute called :studies_level.

有一个名为Student的模型，它有一个名为：studies_level的属性。

studies_level can have one of the following values: ['school_graduate', 'undergraduate', 'graduate', 'postgraduate', 'doctoral', 'postdoctoral']

studies_level可以具有以下价值之一：['school_graduate'，'本科'，'研究生'，'研究生'，'博士'，'博士后']

There is also another model called University

还有另一种叫做大学的模型

If :studies_level is postgraduate then Student must fill the following attributes :undergraduate_university and :postgraduate_university with a University_id

如果：studies_level是研究生，那么学生必须填写以下属性：本科_大学和：University_idiversity with a University_id

Is there any way to achieve this with Rails model relations (belongs_to, etc) ?

有没有办法用Rails模型关系（belongs_to等）来实现这个目的？

1 个解决方案

#1

belongs_to :undergraduate_university, class_name: :University
belongs_to :postgraduate_university, class_name: :University
validates  :undergraduate_university, presence: true, if: :studies_level=='postgrad'
validates  :postgraduate_university, presence: true, if: :studies_level=='postgrad'
validates_associated  :undergraduate_university
validates_associated  :postgraduate_university