Aqui está uma maneira de usar um gatilho INSTEAD OF.
CREATE TRIGGER MyTrigger ON MyTable INSTEAD OF INSERT AS
INSERT MyTable(col1, [other columns])
SELECT UPPER(i.col1)
, i.[other columns]
FROM Inserted i
CREATE TRIGGER MyTrigger ON MyTable INSTEAD OF INSERT AS
INSERT MyTable(col1, [other columns])
SELECT UPPER(i.col1)
, i.[other columns]
FROM Inserted i