shop_process.php

php模块设计。。。里面的模块很有学习价值

<?
	include("db_conn.php");
	include("db_func.php");

	session_start();

	// 若 usermail 变量尚未被注册 session 
	if( ! isset($_SESSION['usermail']) ) 
	{	
		$message = "无法辨识订购者身份";
	}
	else
	{
		// 取出用户的 b_id BEGIN
		$SQLStr = "SELECT * FROM buyer WHERE b_mail = '$usermail'";
		$res = db_query($SQLStr);
		$row = db_fetch_array($res);
		$b_id = $row[b_id];
		// 取出用户的 b_id END
		
		// 取出产品名称及数据 BEGIN
		$SQLStr = "SELECT * FROM product WHERE p_id = '$p_id'";
		$res = db_query($SQLStr);
		$row = db_fetch_array($res);
		$tmp_p_name = $row['p_name'];
		// 取出产品名称及数据 END

		// 查询购物车中是否已有此产品 BEGIN
		$SQLStr = "SELECT * FROM shopcart WHERE s_product = '$tmp_p_name' AND b_id = '$b_id'";
		$res = db_query($SQLStr);
		// 查询购物车中是否已有此产品 END

		if(db_num_rows($res)>0) // 若购物车中已有此产品
		{
			// 将此产品数量累加一 BEGIN
			$SQLStr = "UPDATE shopcart SET s_num=s_num+1 WHERE s_product = '$tmp_p_name' AND b_id = '$b_id'";
			db_query($SQLStr);
			// 将此产品数量累加一 END

			$row = db_fetch_array($res);
			$message = "您的购物车目前已有" . ($row[s_num]+1) . "个此项产品了"; 
		}
		else // 若购物车中无此产品

		{
			$SQLStr = "INSERT INTO shopcart (s_id, b_id, s_product, s_num, s_price) VALUES('', '$b_id', '$row[p_name]', '1', '$row[p_price]')";
			db_query($SQLStr);
			$message = "已将此商品放入您的购物车内"; 
		}
	}
?>
<script>
alert("<?=$message?>");
location.href="product_show.php?p_id=<?=$p_id?>";
</script>