Change the master GridView after detail change?

[Q. John Chen]

I have a gridview control as master table (for example orders)
I have a formView (should be same if a detailView) control for entering
order detail.

Currently, I simply do a databind after formView data Inserted or
Updated. It works but not efficient (I have lot of records in the
orders table).

I am thinking simply update one cell (eg the total amount) in the
master gridView without re-Databind(). How?

THX

John