Переопределение

<?php
    session_start();
    $id = session_id();
    
    class mysqli {  
    private $dblocation = "localhost";
    private $dbname = "test";
    private $dbuser = "root";
    private $dbpasswd = "";
    
    
        public function query($query) {     
        mysqli_select_db($this->dbname, mysqli_connect($this->dblocation, $this->dbuser, $this->dbpasswd));
        return array(mysqli_query($query, mysqli_connect($this->dblocation, $this->dbuser, $this->dbpasswd)));
        mysqli_close(mysqli_connect($this->dblocation, $this->dbuser, $this->dbpasswd));    
        }
    
    
    }
    
    
    $db = new mysqli();
    $result = $db->query("SELECT * FROM online WHERE id = '$id'");
    
    echo $result;
    
    
?>

class Foo{}
class Foo{}
$obj=new Foo;

session_start();
    $id = session_id();
    
    class Mysqli
        {  
    
        private $dblocation = "localhost";
    private $dbname = "test";
    private $dbuser = "root";
    private $dbpasswd = "";
    private $conn = false;
    
        public function __construct() 
        {
            $this -> conn = mysqli_connect($this->dblocation, $this->dbuser, $this->dbpasswd);
            mysqli_select_db($this->dbname, $this -> conn);
        }
        
    public function query($query) {   
            
 
            return array(mysqli_query($query, $this -> conn));
        }
    
    
        public function close() {
            mysqli_close($this -> conn);    
        }
        
    }
    
    
    $db = new Mysqli();
    $result = $db->query("SELECT * FROM online WHERE id = '$id'");
    
    echo $result;