>I've had similar experiences where there isn't a neat and easy solution like an invoice without a Work Order. The redunancy makes a lot of sense. You can default customer information to the Work Order's information if there is one, but you have to allow an invoice without a Work Order.

So it does happen here. Just wondered how people sell things here if there's no explicit order.

>>Equally, storing the state with the ZIP should be OK - I haven't heard of too many cities travelling between states recently.
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>So you don't feel store the State Id? I like the zip idea, but in some cases the user won't know the zip or it may be a new zip that would not have been added to the table yet.

I've been storing zip in customer's record always, but for the sake of speed I've always copied the city name once they found the zip. Back home we had only six states, so the state codes haven't really existed; here I'd store that as well, but for different reasons: addresses abroad. While the zip codes and states here are available, there was a thread here recently which covered that, you may have customers from places which have zip codes you don't have in your table - from anywhere in the rest of the world. In that case I'd just leave the ZIP blank and keep the city and other info in the same fields.

We did have trouble with these stored names at home, because with the fall of communism many cities reverted to their old names. While it's very unlikely that you may have to search for all occurrences of New York and replace with New Amsterdam (which would be a breeze in really normalized situation), there's always this possibility.

So both ways have their pros and cons, YMMV, don't try this at home (go to your neighbor's), and the general answer applies: it depends :).