$con = getCon();
$result = mysqli_query($con, "SELECT * FROM sometable WHERE deleted=0");

class Database{
    private static $db;
    private $connection;

    private function __construct(){
        $servername = "localhost";
        $username = "...";
        $password = "...";
        $dbname = "...";

        $this->connection = new mysqli($servername, $username, $password, $dbname);
    }

    function __destruct() {
        $this->connection->close();
    }

    public static function getConnection(){
        if(self::$db == null){
            self::$db=new Database();
        }

        return self::$db->connection;
    }
}