Add a column TSTAMP CHAR(13) FOR BIT DATA to your table.
Then
CREATE TRIGGER stamp BEFORE UPDATE ON T REFERENCING NEW AS n
FOR EACH ROW
SET N.TSTAMP = GENERATE_UNIQUE();

CREATE TRIGGER stamp BEFORE INSERT ON T REFERENCING NEW AS n
FOR EACH ROW
SET n.TSTAMP = GENERATE_UNIQUE();

If you update your result set you can use MERGE:

MERGE INTO T USING (VALUES (1, 'hello', '<stamp1>), (2, 'world',
'<stamp2>')) AS S(pk, c1, tstamp)
ON T.pk = S.pk AND S.tstamp = T.tstamp
UPDATE SET c1 = S.c1
WHEN MATCHED THEN SIGNAL SQLSTATE '38000' SET MESSAGE_TEXT = 'Row has
changed!'
ELSE SIGNAL SQLSTATE '38000' SET MESSAGE_TEXT = 'Row has been deleted!'

(you can bury that logic into the BEFORE trigger as well if you wish).

Cheers
Serge