SQL

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 

sqlstate[23000]: integrity constraint violation: 1451 cannot delete or update a parent row:

Schema::disableForeignKeyConstraints();
Schema::dropIfExists('tablename');
Schema::enableForeignKeyConstraints();

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

mysql - Cannot delete or update a parent row: a foreign key constraint fails

ALTER TABLE `advertisers`
  ADD CONSTRAINT `advertisers_ibfk_1` FOREIGN KEY (`advertiser_id`) 
      REFERENCES `jobs` (`advertiser_id`);