Fatal error: Uncaught Error: Object of class PDO could not be converted to string in /home/nokhbeparvaran/public_html/include/class.student.php:12 Stack trace: #0 /home/nokhbeparvaran/public_html/main.php(139): ManageStudents->__construct() #1 /home/nokhbeparvaran/public_html/index.php(16): include('/home/nokhbepar...') #2 {main} thrown in /home/nokhbeparvaran/public_html/include/class.student.php on line 12