Re: normalization question

From: toby <toby_at_telegraphics.com.au>
Date: Wed, 29 Apr 2009 17:38:24 -0700 (PDT)
Message-ID: <a58ad58a-c46b-45e2-9f39-b5082b78a73e_at_z16g2000prd.googlegroups.com>



On Apr 28, 5:10 am, "Matko" <mkl..._at_foi.hr> wrote:
> ItemID can't be primary key because its value in every entry is not unique
> ;)

Are you sure? It seems to me that this would correspond to the constraint that an item can be in only one box.

>
> Matko
>
> "toby" <t..._at_telegraphics.com.au> wrote in message
>
> news:9537eaf6-4d8a-46a4-a248-b625465034c7_at_y6g2000prf.googlegroups.com...
> On Apr 27, 4:11 pm, myotheraccount <levt..._at_yahoo.com> wrote:
>
> > That's similar to my first proposed solution, but, like that solution,
> > does not enforce rule #3. For example:
> > R1
> > BoxID, CustomerID, VendorID
> > 1, 1, 1
> > 2, 1, 1
>
> > R2
> > BoxID, ItemID
> > 1, 1
> > 2, 1
>
> > The keys will allow this, but it violates Rule #3
>
> What if the key on R2 is {ItemID} alone?
Received on Wed Apr 29 2009 - 19:38:24 CDT

Original text of this message