php 用checkbox一次性删除多条记录的方法

<form action="sc.php" method=post>
<table border=1 width=60% align=center>
<caption>学生信息表</caption>
<th>选项</th><th>学号</th><th>姓名< /th><th>性别</th><th>电话</th>
<?php
$link=mysql_connect("localhost","root","");
mysql_select_db("zs");
$exec="select * from student";
$result=mysql_query($exec);
while($rs=mysql_fetch_object($result))
{
$id=$rs->sID;
$name=$rs->sName;
$sex=$rs->sSex;
$phone=$rs->sPhone;
?>
<tr>
<td> <input type=checkbox name=de[] value=<?php echo $id?>></td><td><?php echo $id?></td><td><?php echo $name?></td><td><?php echo $sex?></td><td><?php echo $phone?></td>
</tr>
<?php
}
mysql_close();
?>
</table>
<center><input type=submit value="删除"></center>
</form>

<?php
$link=mysql_connect("localhost","root","");
mysql_select_db("zs");
$id=$_POST['de'];
foreach($id as $ide){
$exec="delete from student where sID=$ide";
$result=mysql_query($exec);
if((mysql_affected_rows()==0) or (mysql_affected_rows==-1))
{
    echo "没有找到记录，或者删除时出错";
    exit;
    }
else{
    echo "学生信息已经删除";
    }
    }
    mysql_close();
?>