--Lock the table;

DECLARE @integer_variable int

IF @@trancount = 0

Begin Transaction;

-- Perform Update

Update table

Set Tablename.Seqnr = Tablename.Seqnr + 1

Where Blabla

--Perform Errorhandling !!! (no code inhere)

-- Perform SELECT

Select seqnr

FROM table

Where blabla.

-- Perform Errorhandling...