In article <3ylt9.174224$8o4.28075_at_afrodite.telenet-ops.be>,
joske_at_home <vandenbergeDOTj_at_village.uunet.be> wrote:
>
>If I apply these normalisation (2NF to 3NF) rules to my tables ... I have
>attributes that depend on 'a part' of the key AND a 'non key' attribute.
>I think that I need 'move' these attributes to a new table that get as key
>the 'part key' AND the non-key attribute of the original table ...
>
>Pff ... trying to express in another form ...
>
>Orig table:
>
>ORIG ( pk X, pk Y, Z, data, ...) attribute 'data' depends on X AND Z
>
>After split ...
>
>ORIG (fpkX, pkY)
>NEW (pkX,pkZ, data)
>
>Does it make sence?
Almost; you should also leave the column Z in the original relation. The
general rule is that if you split off a dependency X1,..Xn -> Y1,..,Ym then
1. in the original table you remove Y1,..,Ym
2. you create a new table with columns X1,..,Xn,Y1,..Ym
Received on Wed Oct 23 2002 - 03:02:58 CDT
