Editing could be refered as the process of 
Entering/Changing Information in a client machine.
The information is explicitly available only in the client 
memory.
Updating could be refered as the process of getting the 
those changes Entered in a Database or File permanantly.

editing is the process of changing the data at the design 
time,and update is the process of changing the data at the 
runtime...

Edit means edit some of the old data.
Update means update some old data as new data.

in edit u can change or add something extra in old data at 
design time while in updation u can replace the old data as 
new once at run time...........ok