As a preface, the current behavior isn't inherent to relational databases.
It is inherent to the particular database design that every Access template
or forum answer I've seen uses. The alternative is a design which treats
and stores invoices as entities / events rather than a derived "view",

An approach that fully administers and automatically stores invoices as
entities/events would be quite complicated. But I think it would be less
complicated to make 2 tables and 2 append queries (manually launched from one
button) to store it:

In you base work, create and populate an invoice number field.

Make an "Invoice header info" table with all one-per-invoice type info.
Make an append query to load such data into it for the invoice-at-hand.

Make an "invoice details" table for line item type info. Include the
invoice number field. Make an append query to append all of the line items
for the invoice-at-hand.



An lower-tech solution would be to pdf and store the invoice.

An even lower tech solution would be to print and file/store the invoices.

Sincerley,

Fred


One low tech way would be to print and file the invoices.