有人知道创建联接表迁移并在联接表中指定引用列的特定名称的另一种方法吗？

Question

I have these two models:

 module Studying
  class Student < ApplicationRecord
   has_and_belongs_to_many :instructors,
                        class_name: 'Studying::Instructor',
                        foreign_key: 'studying_student_id',
                        association_foreign_key: 'studying_instructor_id'
  end
end


 module Studying
  class Instructor < ApplicationRecord
   has_and_belongs_to_many :students,
                        class_name: 'Studying::Student',
                        foreign_key: 'studying_instructor_id',
                        association_foreign_key: 'studying_student_id'
  end
end

And for join_table I have generated migration:

def change
  create_table :studying_instructors_students, id: false do |t|
  t.belongs_to :studying_instructor, index: { name: 'index_instructors_students_on_studying_instructor_id' }
  t.belongs_to :studying_student, index: { name: 'index_instructors_students_on_studying_student_id' }
  end
end

So all is working fine, but the point is, that my senior comrade tells me that I should not use in models things such as:

  foreign_key:  'studying_instructor_id',

and

  association_foreign_key: 'studying_student_id'  

but instead of these I should use:

  foreign_key:  'instructor_id', 

and

  association_foreign_key: 'student_id'

and in the same way in the first model because this is against the convention. I do not know how I can do this in this models and in tables (how you already understand tables names in db: studying_instructors and studying_students).

Any advice please ?

Answer 1

You can create relation table this way

def change
  create_table :studying_instructors_students, id: false do |t|
    t.integer :instructor_id, index: true
    t.integer :student_id, index: true
  end
end

and then you can use foreign_key: 'instructor_id', and association_foreign_key: 'student_id'

If I get this wrong way, please, feel free to address additional questions.

Answer 2

I would do something like this:

class Studying::Student < ApplicationRecord
  has_many :student_instructors, class_name: 'Studying::StudentInstructor'
  has_many :instructors, through: :student_instructors, class_name: 'Studying::Instructor'

end

class Studying::Instructor < ApplicationRecord
  has_many :student_instructors, class_name: 'Studying::StudentInstructor'
  has_many :students, through: :student_instructors, class_name: 'Studying::Instructor'      
end

class Studying::StudentInstructor < ApplicationRecord
  belongs_to :student, class_name: 'Studying::Student'
  belongs_to :instructor, class_name: 'Studying::Instructor'      
end

I have three tables here. One for students, second for instructors and third one is a junction table (student_instructors).

Migration for studnt_instructor will look something like this

def change
  create_table :student_instuctors, id: false do |t|
    t.integer :instructor_id, index: true
    t.integer :student_id, index: true
  end
end

I have not verified the syntax but this is more of logic explanation.

I hope this helps.