Question

I’ve got problem with INSTEAD OF trigger in MsSQL. I got an app with some error, and as a quick workaround I don’t want user to modify one exact row in DB.
I created following trigger: (on table)

 create trigger UglyWorkaround ON Configuration instead of update 
  as
    begin
        if (select COUNT(1) from inserted where Key='Key01' and Value<>'2') > 0 begin
            update Configuration set Value='2' where Key='Key01'
        end else begin
            -- DEFAULT ACTION (do update as intended)
        end;


    end;

But I’ve got problem with determining, how to set default action.
Update Configuration set Value=inserted.Value where Key=inserted.Key doesn’t work for me. Is there any way how to do this with triggers? (I know that the solution is bad, but I got no other option, as I can’t change code now.)

Answer 1

inserted is a table, so try joining:

update c set c.Value = i.Value
from Configuration c
    inner join inserted i on c.Key = i.Key

You could also filter out Key01 at the same time, and it wouldn’t matter if they tried to update the value for Key01 to something other than 2.

update c set c.Value = i.Value
from Configuration c
    inner join inserted i on c.Key = i.Key
where i.Key <> 'Key01'