I read this article but it seems not work for delete. I got this error when tried to create a trigger:
Executing SQL script in server
ERROR: Error 1363: There is no NEW row in on DELETE trigger
CREATE TRIGGER DeviceCatalog_PreventDeletion
BEFORE DELETE on DeviceCatalog
FOR EACH ROW
BEGIN
DECLARE dummy INT;
IF old.id = 1 or old.id =2 THEN
SELECT * FROM DeviceCatalog WHERE DeviceCatalog.id=NEW.id;
END IF;
END;
SQL script execution finished: statements: 4 succeeded, 1 failed
Try something like this -
DELIMITER $$
CREATE TRIGGER trigger1
BEFORE DELETE
ON table1
FOR EACH ROW
BEGIN
IF OLD.id = 1 THEN -- Abort when trying to remove this record
CALL cannot_delete_error; -- raise an error to prevent deleting from the table
END IF;
END
$$
DELIMITER ;