class UpdateCourseActivityTime < ActiveRecord::Migration def up count = CourseActivity.all.count / 30 + 1 transaction do for i in 1 ... count do i CourseActivity.page(i).per(30).each do |activity| if activity.course_act if activity.course_act.respond_to?("created_at") activity.created_at = activity.course_act.created_at elsif activity.course_act.respond_to?("created_on") activity.created_at = activity.course_act.created_on end activity.save user_activity = UserActivity.where("act_type = '#{activity.course_act_type.to_s}' and act_id = '#{activity.course_act_id}'").first user_activity.created_at = activity.created_at user_activity.save end end end end end def down end end