Fatal error: Uncaught Error: Class 'Doctrine\DBAL\Event\SchemaEventArgs' not found in E:\xampp\htdocs\www\qr250\vendor\doctrine\dbal\src\Event\SchemaAlterTableAddColumnEventArgs.php:19 Stack trace: #0 {main} thrown in E:\xampp\htdocs\www\qr250\vendor\doctrine\dbal\src\Event\SchemaAlterTableAddColumnEventArgs.php on line 19