Re: Modeling Address using Relational Theory

Marshall Spight wrote:
> Ha ha! I'm posting on this topic again. Clearly
> I have some kind of brain disorder.

If not, you soon will ;-)

Dawn, it seems to me that there is something fundamental to Marshall's argument that you just don't "get", perhaps because you are so ingrained with address lines from everyday use. There is *nothing* intrinsically ordered about addr1, addr2. Putting addr1 before addr2 on an envelop is a convention, that's all. The naming addr1, addr2 is based on that convention, of course, which perhaps adds to the confusion.

What is addr1? Clearly it is the *most specific* part of the address, just as Country (if you have that) is the *least specific* part. One could come up with various alternative names for addr1 - most_speficic_addr, building_and_street (perhaps, but then again perhaps that isn't always an appropriate name), ...

When you print an address, you follow convention and put the attributes in the order addr1, addr2, city, state, zip, country (or whatever). But you don't *have* to! In some countries, it might well be the convention to start with the country at the top and work down to the most specific address line.

Also, for some reports you may want to work backwards, breaking on state then city then addr2 then addr1.

The same applies to names. Some usages will be "Mr Fred Bloggs", others will be "Bloggs, Fred (Mr)" etc.

So while there is a *conventional display order* for address lines, there is no *intrinsic* ordering.

Part of the problem is that addresses are quite complicated, which makes coming up with good attribute names difficult. addr1 and addr2 reflect that difficulty.

I haven't said anything here that Marshall hasn't already said (better), I just thought I'd summarise the main points as I see them, and add my weight to the attempt to tip you over the edge where you can suddenly see what Marshall means! Received on Mon Sep 05 2005 - 14:40:25 CEST