Answers for "SQLSTATE[23000]: Integrity constraint violation: 1451 Cannot delete or update a parent row: a foreign key constraint fails"

error 1451 (23000): cannot delete or update a parent row: a foreign key constraint fails

SET FOREIGN_KEY_CHECKS = 0; -- to disable FK checks (ex: for delete purpose)
SET FOREIGN_KEY_CHECKS = 1; -- to re-enable FK checks

ERROR 1451: 1451: Cannot delete or update a parent row: a foreign key constraint fails

SET FOREIGN_KEY_CHECKS=0; -- to disable them
SET FOREIGN_KEY_CHECKS=1; -- to re-enable them