Cascading Combo, from Unbound combo, plus push back from unbound text box

This cascading Combo box sample, is an example of a Post Code (Zip Code) database, with a State, Suburb schema (using a fully normalise table structure) with the ability to push back a selection from an unbound Post Code Text box.

The DB shows how a combo box can cascade from an initial unbound Combo Box (State) to a bound Combo Box (Suburb), and maintain synchronisation between the two combo boxes as the user scrolls through the record set. It also gives the user the option to enter a post code in an unbound text box, have it validated, and push the associated data back into the bound and also unbound Combo Box.