Question

Given the following code, which enroll method is better and why? Or should this code be improved some other way altogether?

My idea of “better” for the above basically boils down to 1) most philosophically correct (best practices) and 2) most efficient/performant.

Class Course < ActiveRecord::Base
  has_many :enrollments # basically a join table
  has_many :students, :source => :user, :through => :enrollments
  def enroll_this_way(student)
    self.enrollments << Enrollment.new(:course_id => self.id, :student_id => student.id)
  end
  # OR
  def enroll_that_way(student_id)
    self.enrollments << Enrollment.new(:course_id => self.id, :student_id => student_id)
  end
end

Answer 1

def enroll_this_way(student)
  self.enrollments.build :student => student
end