1class MigrateTrainingSessionIdToExerciseSets < ActiveRecord::Migration
 2  def change
 3    ExerciseSet.where(training_session_id: nil).find_each do |set|
 4      result = execute(
 5      <<-SQL
 6SELECT training_session_id
 7FROM exercise_sessions
 8WHERE id = '#{set.exercise_session_id}'
 9      SQL
10      )
11      training_session_id = result.first["training_session_id"]
12      say "updating set: #{set.id} to training_session: #{training_session_id}"
13      set.update_column(:training_session_id, training_session_id)
14    end
15  end
16end