INSERT INTO `mytable` VALUES (1,'created by root','root'),(4,'created by helen','helen'),(6,'created by helen1','helen'),(7,'123','lina');

select * from mytable

create trigger enforce_insert before insert on mytable for each row if NEW.owner != substring_index(user(), '@', 1) then signal sqlstate '45000' set message_text = 'conflict of owner on insert'; end if

INSERT INTO mytable VALUES (1,'created by root', 'somebodyelse');

INSERT INTO mytable(title) VALUES (concat('created by ', user()))

create trigger enforce_update before update on mytable for each row if OLD.owner != substring_index(user(), '@', 1) OR NEW.owner != substring_index(user(), '@', 1) then signal sqlstate '45000' set message_text = 'conflict of owner on update'; end if

update mytable set title=concat(title, ' modified') where title = 'created by root'

update mytable set title=concat(title, ' modified') where owner=substring_index(user(), '@', 1)

create trigger enforce_delete before delete on mytable for each row if OLD.owner != substring_index(user(), '@', 1) then signal sqlstate '45000' set message_text = 'conflict of owner on delete'; end if

select * from mytable

delete from mytable where title = 'created by root'

delete from mytable where owner=substring_index(user(), '@', 1)

select * from mytable