Just because Acct_Name appears in two tables does not mean that the model is
denormalized. The choice of a natural key (Acct_Name) versus a surrogate key
(Acct_Id) has nothing to do with normalization. However, natural keys often
have undesirable properties, so a surrogate keys make a better
implementation.
"stanky" <stanky_at_stanky.net> wrote in message
news:GhVG7.23105$lV4.1942030_at_e420r-atl1.usenetserver.com...
> Let's say we have the following query:
>
>
> SELECT A.Acct_Id, B.*
> FROM Account A,
> Claims B
> WHERE A.Acct_Id = B.Acct_Id /* A.Acct_Id = primary index and
B.Acct_Id
> = foreign index referencing Account table
> and both
> columns are populated from values generated by an Oracle Sequence */
> AND A.Acct_Name = 'Campbell Soup';
>
>
>
>
> WIll the join make use of the index in this situation? I'm in the process
> of trying to design a normalized database for my group. I'm obviously not
a
> database modeler but it's a small collection of tables so I've volunteeed
> for the job.
>
> I'm trying to determine whether it makes more sense to use Sequences to
> generate the values for the keys of certain tables or just to use the
actual
> values like Acct_Name. It seems to me, in the case of the query above,
that
> the index is almost useless because you're always having to specificy an
> additional criteria along with the join predicate.
>
> In the tables that I'm working with currently, the keys of the following
> two tables are Acct_Name. But I understand that violates normalization
> rules because Acct_Name is then stored in more than one table. Any advice
> would be greatly appreciated.
>
> Thanks.
>
>
>
>
>
Received on Fri Nov 09 2001 - 15:16:36 CST
