使用面向对象封装类实现连接数据库

<?php




class conn
{
    var $host='localhost';
    var $user='root';
    var $pass='';
    var $db='test';
    var $point='3306';




    function  connect(){
        $connect=mysqli_connect("localhost","root","","test","3306");
        if (mysqli_query($connect,"set names utf8")){
            return true;
        }
        else{
            return false;
        }
    }
            function sel($sql){
                $connect=mysqli_connect("localhost","root","","test","3306");
                $res=mysqli_query($connect,$sql);
                return $res;
            }
            function fetch($a){
                         return mysqli_fetch_assoc($a);
            }




}