Listing 6: Code That Stores System Function Values Separately
/* Update fails with a trappable error. */

UPDATE table1           
SET  col1 = 'x'
WHERE …..                                               -- @@ERROR = non-zero
                                                                   -- @@ROWCOUNT = 0


SELECT @row_count = @@ROWCOUNT    -- @row_count = 1,   @@ERROR = 0
SELECT @error_stat  = @@ERROR             -- @@ERROR = 0,    @error_stat = 0

IF @error_stat <> 0                                   -- @error_stat = 0
   ROLLBACK                                            -- Rollback never executed.
etc …..