<?php
//連接數(shù)據(jù)庫
$con=mysqli_connect("192.168.2.186","root","root","test");
//查詢商品數(shù)量是否大于0,大于0才能下單,并減少庫存
$fp = fopen("lock.txt", "r");
//加鎖
if(flock($fp,LOCK_EX))
{
  $res=mysqli_fetch_assoc(mysqli_query($con,'SELECT total FROM shop WHERE id=1 LIMIT 1'));
  if($res['total']>0){mysqli_query($con,'UPDATE shop SET total=total-1 WHERE id=1');}
  //執(zhí)行完成解鎖
  flock($fp,LOCK_UN);
}
//關(guān)閉文件
fclose($fp);
unset($res);
mysqli_close($con);
?>