Fatal error: Uncaught mysqli_sql_exception: Cannot add or update a child row: a foreign key constraint fails (`allahuak_project.billboard.allahuakbar.media`.`visitors`, CONSTRAINT `visitors_ibfk_1` FOREIGN KEY (`presentation_id`) REFERENCES `presentations` (`id`) ON DELETE CASCADE) in /home/allahuak/project.billboard.allahuakbar.media/display_view.php:17 Stack trace: #0 /home/allahuak/project.billboard.allahuakbar.media/display_view.php(17): mysqli_stmt->execute() #1 {main} thrown in /home/allahuak/project.billboard.allahuakbar.media/display_view.php on line 17