class CreateCourseClassroms < ActiveRecord::Migration[6.0]
  def change
    create_table :course_classrooms, id: false do |t|
      t.references :course, null: false, foreign_key: { to_table: :courses }
      t.references :classroom, type: :integer, null: false,
        foreign_key: { to_table: :Classes, primary_key: :ClassID }

      t.index [:course_id, :classroom_id], unique: true
    end
  end
end