Re: Modeling Address using Relational Theory

Marshall Spight wrote:
> Gene Wirchenko wrote:
> > On 29 Aug 2005 20:49:44 -0700, "dawn" <dawnwolthuis_at_gmail.com> wrote:
> > >
> > >I understand the Line1, Line2, Line3 implementation, but any model with
> > >those attributes screams "this model is not relational", right? I am
> >
> > No. It is not 1NF if the attributes can have other than one
> > value, but the names are irrelevant except that they be unique within
> > the relation.
>
> Agreed. Line1 and Line2 are not two interchangable instances of
> the same kind of thing; they are specific distinct fields. It
> is not a repeating group.

I realize it is not a repeating group, but I thought that having Major1, Major2, Major3 or AddressLine1, AddressLine2, AddressLine3 violated relational modeling principles. Are you saying that this is just fine? If I understand correctly, it is fine because line1 is the first line, where line2 is the second line, so they are different attributes? So, if you want to have a person's name and up to 4 of their former names, does it violate relational principles to have these as attributres Name, FormerName1, FormerName2, FormerName3, FormerName4? The most recent former name is decidedly a different type than the one before that. If relational theory supports lists made in this fashion, I find that really fascinating, don't you?

Thanks. --dawn Received on Tue Aug 30 2005 - 21:01:24 CEST