How to specify a query as read only

I think INSTEAD OF trigger would be cheaper in cost than AFTER trigger.

You might try adding DISTINCT or GROUP BY to the view, that usually makes the resultset uneditable in client apps.

I would rather not add distinct or group by to view definition. Computed column would work faster in this case, we can take smallest computaion to make it light weight.

The computed column worked like a charm. Now I don't need triggers![]

Maybe not quite what you are looking for but you can have a view where two different users see different things depending on their scheme.CREATE
VIEW [dbo].d1 AS select col1, col2, col3 from tablenameCREATE
VIEW [guest].d1 AS select col1, col2 from tablenameEXECUTE
AS LOGIN ='regularuser'
SELECT * FROM d1
REVERT
EXECUTE AS LOGIN ='guestuser'
SELECT * FROM d1
REVERT