before.each do |pre_id|

  after.each do |post_id|
   puts "post id " + post_id[1] + " and pre id " + pre_id[1]
    if pre_id[1] == post_id[1]
      @store_id = post_id[0]
    end
  end

  puts "inserting " + @store_id + " which is replacing " + pre_id[0]
  sql.query("UPDATE tabs SET product_id='#{@store_id}' WHERE product_id='#{pre_id[0]}';")
end