Fatal error: Uncaught mysqli_sql_exception: Cannot delete or update a parent row: a foreign key constraint fails (`monabani_calc`.`formulas`, CONSTRAINT `formulas_ibfk_2` FOREIGN KEY (`material_id`) REFERENCES `materials` (`id`)) in /home/monabani/public_html/calc.anseandbeauty.com/delete_material.php:19 Stack trace: #0 /home/monabani/public_html/calc.anseandbeauty.com/delete_material.php(19): mysqli->query() #1 {main} thrown in /home/monabani/public_html/calc.anseandbeauty.com/delete_material.php on line 19