Fatal error: Uncaught PDOException: SQLSTATE[23000]: Integrity constraint violation: 1451 Cannot delete or update a parent row: a foreign key constraint fails (`training`.`sessie_details`, CONSTRAINT `sessie_details_ibfk_2` FOREIGN KEY (`dag_oefening_id`) REFERENCES `dag_oefeningen` (`id`)) in /var/www/html/oefeningen.php:60 Stack trace: #0 /var/www/html/oefeningen.php(60): PDOStatement->execute(Array) #1 {main} thrown in /var/www/html/oefeningen.php on line 60