如何从页面向数据库插入信息（PHP实例）

PHP页面

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<?php
//初始化act
$_REQUEST['act']=$_REQUEST['act']?$_REQUEST['act']:'';
if($_REQUEST['act']=='add'){
 include 'templates/zhiliang_add.php';
 }elseif($_REQUEST['act']=='insert'){       //文件上传  
     //var_dump($new_file_name);
     $title=$_POST['title'];
     $content=$_POST['content'];
     $time=$_POST['time'];
     include 'db.class.php';
     $db=new db('localhost','root','123','fanyi');
     $sql="insert into zhiliang values(null,'$title','$content','$time')";
     if(mysql_query($sql)){
       echo "添加成功"; 
  &