PHPがページからデータベースに情報を挿入する方法のサンプルコードの詳細な説明

 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<?php
//初始化act
$_REQUEST[&#39;act&#39;]=$_REQUEST[&#39;act&#39;]?$_REQUEST[&#39;act&#39;]:&#39;&#39;;
if($_REQUEST[&#39;act&#39;]==&#39;add&#39;){
 include &#39;templates/zhiliang_add.php&#39;;
 }elseif($_REQUEST[&#39;act&#39;]==&#39;insert&#39;){       //文件上传  
     //var_dump($new_file_name);
     $title=$_POST[&#39;title&#39;];
     $content=$_POST[&#39;content&#39;];
     $time=$_POST[&#39;time&#39;];
     include &#39;db.class.php&#39;;
     $db=new db(&#39;localhost&#39;,&#39;root&#39;,&#39;123&#39;,&#39;fanyi&#39;);
     $sql="insert into zhiliang values(null,&#39;$title&#39;,&#39;$content&#39;,&#39;$time&#39;)";
     if(mysql_query($sql)){
       echo "添加成功"; 
      }     
     }