I've gotten it to work manually. In this example, I'm using a DataGrid with a table called accounts and selecting 3 fields acct_name, contact, full_name where acct_name is the primary key.

The select statement is:
SELECT acct_name, contact, full_name FROM accounts

The update statement is:

UPDATE accounts
SET contact = ?, full_name = ?
WHERE (acct_name = ?)

Apparently, if you map your field names the same, the ? is shorthand for the same field name.

This one sets both the full_name and contact columns to the value you type into the contact column.

UPDATE accounts
SET contact = ?, full_name = contact
WHERE (acct_name = ?)

What a painful experience!

Mike