PHP插入数据库代码，编辑，删除

<?
$action=$_GET['action'];
switch($action){
//添加记录
case"add";
$mail = trim(htmlspecialchars($_POST["mail"]));
$username = trim(htmlspecialchars($_POST["username"]));
$tel = trim(htmlspecialchars($_POST["tel"]));
$fax = trim(htmlspecialchars($_POST["fax"]));
$company = trim(htmlspecialchars($_POST["company"]));
$address = trim(htmlspecialchars($_POST["address"]));
$sql="insert into crm_company (mail,username,tel,fax,company,address,addtime) values ('$mail','$username','$tel','$fax','$company','$address','$addtime')";
//echo $sql;
mysql_query($sql,$conn);
print "<mce:script type="text/javascript"><!--
location.href='c_companylist.php';
// --></mce:script>";//*/
}?>

<?
$action=$_GET['action'];
switch($action){
//添加记录
case"edit";
$uid = trim(htmlspecialchars($_POST["uid"]));
$regtime = trim(htmlspecialchars($_POST["regtime"]));
$deadline = trim(htmlspecialchars($_POST["deadline"]));
$item = trim(htmlspecialchars($_POST["item2"]));
$price = trim(htmlspecialchars($_POST["price"]));
$product = trim(htmlspecialchars($_POST["product"]));
$content = trim(htmlspecialchars($_POST["content"]));

$sql="update crm_info set uid='$uid',regtime='$regtime',deadline='$deadline',item='$item',price='$price',product='$product',content='$content' where id='$id'";
//echo $sql;
mysql_query($sql,$conn);
print "<mce:script type="text/javascript"><!--
location.href='c_infolist.php';
// --></mce:script>";//*/
}?>

<form id="form1" name="form1" method="post"  action="?action=edit&id=<?php echo $rs['id'];?>" onSubmit="return checkadd()">

</form>

<a href="?action=del&id=<? echo $rs['id'];?>" onclick="return confirm('确定删除?')">删除</a>

<?
$action=$_GET['action'];
switch($action){
//删除记录
case"del";
$id=$_GET['id'];
$sql="delete from crm_info where id='$id'";
mysql_query($sql,$conn);
print "<mce:script type="text/javascript"><!--
location.href='c_infolist.php';
// --></mce:script>";
break;
}

?>