Rails: get belongs_to class_name

Question

I have a base class Entry, with lots of different subclasses. Such as:

class Entry < ActiveRecord::Base
    ...
end

class UserEntry < Entry
    belongs_to :target, class_name: User
end

Is there a way to retrieve the class_name of the target association of the UserEntry class? It should return User.

Answer 1

You are doing the right thing, except class_name should be a String, not Class

class UserEntry < Entry belongs_to :target, class_name: 'User' end

Answer 2

我想我找到了我正在寻找的东西：ActiveRecord::Reflection类方法（之前的答案很有帮助，但没有真正回答这个问题）

我使用reflect_on_association类方法来获取:target关联的详细信息。所以为了得到我想要的东西，我做了：

UserEntry.reflect_on_association(:target).klass，返回User类。

Answer 3

请务必在primary_key中设置foreign_key和belongs_to，因为AR不够智能，无法将user_id映射到target_id