class Legacy
  def self.clear_period
    begin
      count = 0
      puts '---------------------'

      Course.transaction do
        Course.all.each do |course|
          if course.class_period =~ /^\D*$/
            count += 1
            puts "[#{course.id}]: #{course.name}"
            puts "period #{course.class_period} ===> 0"
            puts '---------------------'
            course.class_period = '0' 
            course.save
          end
        end # each end
      end # transaction end

      puts "clean period count: #{count}"
    rescue Exception => ex
      puts "*** transaction abored!"
      puts "*** errors: #{ex.message}"
    end
  end
end