PHP实现一个多功能购物网站的案例

<?php
session_start();
$zj = $_GET["zj"];
//如果该水果数量大于1,减1
//如果该水果数量等于1 移除
$arr = $_SESSION["gwd"];
if($arr[$zj][1]>1){
 $arr[$zj][1]=$arr[$zj][1]-1;
}else{
 unset($arr[$zj]); //清除数组
 $arr=array_values($arr); //重新索引数组
}
$_SESSION["gwd"] = $arr;
header("location:add_list.php");

<?php
session_start(); 
$ids = $_GET["ids"];
//查看余额
$uid = $_SESSION["uid"];
require_once "./DBDA.class.php";
$db = new DBDA();
$sql = "select account from login where username='{$uid}'";
$arr = $db->query($sql,0);
$aye = $arr[0][0];//余额
//var_dump($aye);
if(!empty($_SESSION["gwd"])){
 $arr = $_SESSION["gwd"];
 $sum = 0;
 //$numbers = count($arr);
 foreach($arr as $v){
  $sql = "select * from fruit where ids='{$v[0]}'";
  $price = $db->query($sql,0);
  $dj = $price[0][2];
  $sum = $sum+$dj*$v[1];
 } 
}else{
 echo "您还未购买商品!";
 //header("shopping_list.php");
 exit;
}
//判断余额是否满足购买
if($aye>=$sum){
 //判断库存
 foreach($arr as $v){
  $skc = "select name,numbers from fruit where ids='{$v[0]}'";
  $akc = $db->query($sql,0);
  var_dump($akc);
  $kc = $akc[0][4];//库存
  //var_dump($kc);
  
  if($kc<$v[1]){
   echo "库存不足!";
   exit;
  }
 }
 //提交订单
 //账户扣除余额
 $skye = "update login set account=account-{$sum} where username='{$uid}'";
 $zhye = $db->query($skye);
 
 //扣除库存
 foreach($arr as $v){
 $skckc = "update fruit set numbers=numbers-{$v[1]} where ids='{$v[0]}'";
 $sykc = $db->query($skckc);
 }
 //添加订单
 $ddh = date("Y-m-d H:i:s");
 $time = time();
 $stjd = "insert into orders values('{$time}','{$uid}','{$ddh}')";
 $wcdh = $db->query($stjd);
 //添加订单详情
 foreach($arr as $v){
  $ddxq = "insert into orderdetails values('','{$ddh}','{$v[0]}','{$v[1]}')";
  $axq = $db->query($ddxq);
 } 
}else{
 echo "余额不足,请充值!";
 exit;
}
header("location:shopping_list.php");