Thank you Mark! Naming the fields to match the DB columns makes things a lot easier. It works!
In a nut shell, I have a form with 2 fields:
Invoice_ID and Lease_ID(Invoice_ID is pre-populated by a database sequence).
Inside the form, I have a listview with the details.
TRANSACTION_TYPE, AMOUNT, DESCRIPTION
I have Add Row and Delete Row buttons to increase/decrease the number of rows in the ListView (for the number of charges for each invoice).
Each row in the database will essentially be:
INVOICE_ID, LEASE_ID, TRANSACTION_TYPE, AMOUNT, DESCRIPTION. (There are other fields but they will be auto-populated at the database level).
To use the INVOICE_ID and LEASE_ID fields without any transformer or JS mapping, I simply created 2 "non-visible" fields in the ListView and pre-populate them by copying over the values from the form.
I think this simplifies everything and seems to work!
Given the screenshot example you've provided, what if I wanted to manipulate data before insert? For example, the ID values (123, 4423, 234) - if I wanted to multiply them by 10 before inserting them, is there a way to do this in one step here?