Rails has_many：通过命名空间 - 未初始化的常量

I'm having some trouble defining a has_many :through relationship in Rails 5 where the join and target models both reside within a namespace. I have a Student model that I want to join to Admission::Application through Admission::ApplicationStudent. When I attempt to access the admission_applications association I get a NameError: "uninitialized constant Student::Application".

我在定义一个has_many：在Rails 5中的关系时遇到一些麻烦，其中连接和目标模型都位于命名空间内。我有一个学生模型，我想通过Admission :: ApplicationStudent加入Admission :: Application。当我尝试访问admission_applications关联时，我得到一个NameError：“未初始化的常量Student :: Application”。

Here are my model definitions:

以下是我的模型定义：

student.rb

student.rb

class Student < ApplicationRecord
  has_many :admission_application_students,
    class_name: 'Admission::ApplicationStudent',
    inverse_of: :student
  has_many :admission_applications,
    through: :admission_application_students,
    source: :application
end

admission/application_student.rb

入院/ application_student.rb

class Admission::ApplicationStudent < ApplicationRecord
  belongs_to :application
  belongs_to :student,
    class_name: 'Student',
    inverse_of: :admission_application_students
end

admission/application.rb

入院/ application.rb中

class Admission::Application < ApplicationRecord
  has_many :application_students
  has_many :students,
    through: :application_students,
    source: :student
end

Incidentally, I generated all three models with standard commands:

顺便说一句，我使用标准命令生成了所有三个模型：

rails g model student
rails g model 'Admission::Application'
rails g model 'Admission::ApplicationStudent'

The application_students and students associations are both functioning correctly from Application. I can also retrieve a collection of ApplicationStudent records from the admission_application_students association on Student. If Student knows how to make it that far, it seems like :source has to be the problem, but I've been researching and testing since yesterday, and I no longer feel like I'm making progress. Any help would be appreciated.

application_students和学生关联都在Application中正常运行。我还可以从Student上的admission_application_students关联中检索ApplicationStudent记录的集合。如果学生知道如何做到这一点，似乎：来源必须是问题，但我从昨天起一直在研究和测试，我不再觉得我在取得进展。任何帮助，将不胜感激。

1 个解决方案

#1

You need to specify the class_name for admission_applications association since it is also in a different namespace:

您需要为admission_applications关联指定class_name，因为它也位于不同的命名空间中：

class Student < ApplicationRecord
  has_many :admission_application_students, class_name: 'Admission::ApplicationStudent'
  has_many :admission_applications, 
                 through: :admission_application_students, 
                  source: :application, 
              class_name: 'Admission::Application'
end

For more information see the documentation for has_many and Section 3.4 Controlling Association Scope of the Active Record Associations Guide.

有关更多信息，请参阅has_many文档和“3.4活动记录关联指南控制关联范围”。

#1