Lets say your dataflow is returning the following dataset with five records to the sql command statement:
ID FirstName LastName
1 Tom Smith
2 Frank Thomas
3 Fred Simpson
4 Jackie Robinson
5 Debra McMillian
You can update this in your database by just writing a Update statement:
UPDATE tblMyTable
SET FirstName = ?, LastName = ?
WHERE ID = ?
So for each row in your dataflow this update statement will run and update that row in your database (the ? will get replaced with the value in that field).
Thanks,
Strick