> If there are not too many detail records the best option is usually to
> create a view that gives a "Total" field which dynamically sums the
> values from the detail records.
>
> If you want to display this field reasonably dynamically at the client
> you may decide to have a second detail table, one-to-one with the
> master that selects the sum of the detail records. After posting a
> normal detail record refresh the sum dataset.
>

Thank You Geoff . These two above are the ones I also thougt to apply.
If the detail records are more , I am thinking the second choce with not
summing up the detail records but updating it everytime using a pessimistik
locking. In this case maybe at the bacground I have to write a delay
routine if there is a conflict. Because every client will lock the record
just for a short time, this solution will not bother clients much. What do
you say ?

Metin Gonen