Re: How long is long enough for primary key ?

krislioe_at_gmail.com wrote:
> Hi,
>
> In our design, lookup tables (Customers, Products etc..) are using
> natural key as PK. We use VARCHAR2(30) as PK column.
>
> Is it too long ? How long is too long ?
>
> Thank you,
> xtanto

Length is irrelevant.
How many bytes is the data required to uniquely define a record?

The only thing that matters are:

First Normal Form:
Make a separate table for each set of related attributes and uniquely identify each record with a primary key.

Second Normal Form
tables do not have composite primary keys

Third Normal Form
all non-key fields are dependent on the primary key

Everything else is window dressing related to performance. And you don't mention anything performance related in your inquiry.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace x with u to respond)
Puget Sound Oracle Users Group
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