Question

I have a Rails 3 app with the following relationship between models:

Course ---[ 1:n ]---> Module

And when an user enrolls into a Course I have this:

Enrollment ---[ 1:n ]---> ModuleStatus

Each Enrollment also always have an user and a course

QUESTION: How can I enforce that when an Enrollment is created for an user, the system goes ahead and creates a ModuleStatus for each of the modules that the given Course has?

Should I use a callback to enforce this creation?

If so, what callback is suitable here? Would it be after_create?

Thanks!

Answer 1

Short answer: yes, using after_create certainly makes sense. It would probably look something like this (obviously you can fill in the details of your modelling).

class Enrollment
  belongs_to :user
  belongs_to :course
  has_many :module_statuses

  after_create :generate_module_statuses

  def generate_module_statuses
    self.course.modules.each do |module|
      self.module_statuses.create(:the_correct_attributes)
    end
  end

end