Hello, Mike.

> ... it is easy enough to kill the transaction if multiple rows are inserted by placing the following snippet at the top of your trigger.
>
>

>DECLARE @rowcnt int
>SET @rowcnt = @@ROWCOUNT
>IF @rowcnt > 1
> BEGIN
> RAISERROR ('your error message'), 16, 1
> ROLLBACK TRANSACTION
> END
>

>
>

I incorporated this snippet in the trigger

>Also, I think you've left yourself open to duplication if concurrency is high enough.
>
>

>set @nNext=(select top 1 pksm+1 from cpu where pksm is not null
>and pksm+1 not in (select pksm from cpu where pksm is not null)
>order by 1)
>

>
>this section does not hold any locks. Since it is a read operation, SQL Server will only use Shared locks. there is nothing that prevents two connections from entering the trigger and getting the same number. the possibility of it happening depends on the number of concurrent inserts into the table.
>

Hold on for a moment, please.
I always thought that for the same table only _one_ trigger can fire at the same time, that’s why i did not even consider turning any locks. Was i wrong?
Best wishes :)
Kamil.