Re: PO generator
To add to Doc's post, can you walk us through how you envision someone using the system? Start with the person taking an order. What do they need to know? What do they record?
Remember that as soon as you say "And the second", you will normally be looking at a child table (or tables) for what you record.
By walking through what you expect, you can sit down with those who do and see if it meets what THEY need. This is often done with end users so that you can avoid big issues later.