how to programmaticaly insert a row into database table

[Juli V.]

I've got a form from Data Connection. There are 3 tables, related with each
other by FK. There is the simple hierarchy:
Table1: id1, field1
Table2: id2, id1, field2
Table3: id3, id2, field3

I want to insert, for example, a row into Table3 with reference to Table2.
So the interface should be following:

To choose an item from Table2 usig dropdown box and fill appropriate fields
for Table3. As a result - only one insert into Table3 with correct id2. No
refference to Table1! How can I make that query? Can I do it without coding?

I can't understand the way of doing that! Is it possible and if it is - how?

Thanx for any help!