db_class.php

<?php
class database{
   // properti
   private $dbHost;
   private $dbUser;
   private $dbPass;
   private $dbName;
   public $mysqli;

    function __construct(){
       $this->dbHost="localhost";
       $this->dbUser="root";
       $this->dbPass="12345";
       $this->dbName="perpustakaan";
       $this->mysqli   = new mysqli($this->dbHost, $this->dbUser, $this->dbPass, $this->dbName);

        /* check connection */
        if (mysqli_connect_errno()) {
            printf("Connect failed: %s\n", mysqli_connect_error());
            exit();
        }
        else {//echo "Koneksi Berhasil";
        }
    }
}

?>