As it says in the title, I am trying to fill in a has_many relationship while creating a new record, but everything that I’ve been able to find requires the record to already exist before filling in the has_many.

Here’s the setup that I have:

schema "course" do
  has_many(:tiers, CourseTiers)
end

schema "tier" do
  has_many(:courses, CourseTiers)
end

schema "course_tiers" do
  belongs_to(:course, Course)
  belongs_to(:tier, Tier)
  field(:order, :integer)
end

The problem comes whenever I try to create a course with the reference to the tiers in the same changeset as the new course. Since neither the course_tiers nor the course exist yet, I haven’t been able to use either build_assoc, cast_assoc, or put_assoc effectively.

Is there any workaround to this that does not involve using multi or performing the insert operation in multiple steps?