We usually provide database users with Combo Box controls in a Form to limit the data that the user may select from. However, if the data isn\’t already present in the underlying database table, then you must provide the user with an easy way to add new items to the list. We saw this approach in a previous tutorial on How to use the Microsoft Access Not In List event of a combo box

This previous tutorial is fine when adding a single field value to the underlying database table. What happens if the combo box contains multiple fields that need values adding to the table?

via Using Not In List with Multiple Fields | Database Solutions for Microsoft Access | databasedev.co.uk.