NORMALIZING A DATA MODEL - A Developer's Guide to Data Modeling for SQL Server - page 83

that album names and dates are always entered in order and not changed
afterward?
There are two ways to eliminate the problem of the repeating group.
First, we could add new attributes to handle the additional albums, as in
Table 4.2.

Table 4.2 Artists and Albums: Eliminate the Repeating Group, but at What Cost?

Artist Album Release Album Release

Name Genre Name 1 Date 1 Name 2 Date 2

The Awkward Rock Home 10/01/2006 NULL NULL

Stage
Girth

Metal On the Sea 5/25/1997 NULL NULL

Wasabi Adult Spicy 11/12/2005 NULL NULL

Peanuts Contemporary Legumes

Rock

The Bobby R&B Running 7/27/1985 Live! 10/30/1988

Jenkins Band the Game

Juices of Brazil Latin Jazz Long Road 1/01/2003 White 6/10/2005

We've solved the problem of the repeating group, and because no at-
tribute contains more than one value, this table is in 1NF. However, we've
introduced a much bigger problem: what if an artist has more than two al-
bums? Do we keep adding two attributes for each album that any artist re-
leases? In addition to the obvious problem of adding attributes to the
entity, in the physical implementation we are wasting a great deal of space
for each artist who has only one album. Also, querying the resultant table
for album names would require searching every album name column,
something that is very inefficient.
If this is the wrong way, what's the right way? Take a look at Tables 4.3
and 4.4.

Table 4.3 The Artists

ArtistName Genre

The Awkward Stage Rock

Girth Metal

Wasabi Peanuts Adult Contemporary Rock

The Bobby Jenkins Band R&B

Juices of Brazil Latin Jazz