db gw sendiri

<?php

$connect=array( 'localhost','root','');
$db=new myDB($connect);
$db->setError(1);
$db->setDB('work_sejahtera');


$sql="select * from klinik_daftar limit 2";
//mengeluarkan 1 data
$data=$db->resOne($sql);
print_r($data); echo '<hr/>';
//mengeluarkan lebih dari 1 data
$data=$db->result($sql);
print_r($data); echo '<hr/>';

//ganti db
$db->setDB('test');
//===ERROR
$db->setError(0);
$sql="select * from dosen1 limit 1";
$db->query($sql);
echo $db->error()."<br/>";

$sql="select * from dosen limit 1";
$data=$db->resOne($sql);

print_r($data); echo '<hr/>';


class myDB{
private $host,$user,$pass,$db;
private $conn;
private $err=0; //only warning 1: stop!! and warning
public $msg,$errMsg;
/*
    hanya 1 data
*/
    function resOne($sql)
    {
        $res=$this->query($sql);
        if($res){

            return $res->fetch_assoc();
        }else{
            return false;

        }

    }
/*
    data lebih dari satu. saran untuk memberi limit
*/
    function result($sql)
    {
        $ar=array();
        $res=$this->query($sql);
        if($res){
            while ($row = $res->fetch_assoc()) {
                $ar[]=$row;
            }

            return $ar;
        }else{
            return false;

        }

    }

/*
query sederhana
*/
    function query($sql){
      $db = $this->conn;
      if(!is_object($db)){
        $this->connect();
        $db= $this->conn;
      }else{

      }
/*
    agar mudah dibaca
*/
       if ($result = $db->query($sql)) {

        $this->res=$result;
        return $result;
       }else{
         $this->error("error :".$db->error );
         return false;
       }

    }

/*
Aktif dan Non-aktifkan error
*/
    function setError($stat=0){
        $this->err=$stat;
    }
/*

*/
    function error($str='')
    {
        if($str==''){
            return $this->errMsg;
        }

        if($this->err==0){
            $this->errMsg=$str;
        }else{
            die($str);
        }
    }

    function __construct($param=array() ){
/*
Disarankan memakai array dengan posisi host, user, pass dan database
*/
        $this->host=$param[0];
        $this->user=$param[1];
        $this->pass=$param[2];
        $this->db=isset($param[3])?$param[3]:'';
    }
/*
    set database
*/
    function setDB($db)
    {
        $this->db=$db;
        $this->conn='';

    }
/*
connect
saat dibuat tidak akan connect kecuali ada proses.
*/
    function connect()
    {
        $this->conn='';

        $this->conn=new mysqli($this->host, $this->user, $this->pass, $this->db);
        if (mysqli_connect_errno()) {
            $this->conn='';
            if($this->err==0){
                $this->errMsg= $this->msg=sprintf("Connect failed: %s\n", mysqli_connect_error());
            }else{
                printf("Connect failed: %s\n", mysqli_connect_error()); die();
            }

        }
    }
/*
    bila di cetak
*/
    public function __toString() {
        return $this->msg;
    }

}