Re: Is it necessary to have Primary keys?

1. The purpose of a primary key is three-fold: . to enable the unique identification (and location) of a given row . thereby to prevent duplicate rows being stored . to ensure that related rows have something to relate to
2. Relational purists insist that a table without a primary key is not a relation within the fullest definition of the term.
3. Oracle does not insist on primary keys.
4. The inclusion of a date column in a primary key *is* a good idea in many cases (and may be essential for any/all of the reasons in 1).
5. Having a date-time column as a *non-leading* part of the key does not carry a particularly large overhead.

Hope this helps.

Chrysalis.

Lisa M. Lewis wrote:
>
> Could anyone tell me if it is necessary to have Primary Keys defined on
> all tables in your database. Are there any disadvantages to not having
> primary keys defined? This particular database is used only to run
> large batch transactions against for gathering statistics, etcs. I will
> have duplicate records in my table ( except perhaps for the date/time).
> I don't believe it is wise to put a date in a primary key. I'm a little
> concerned because I have always heard that it is necessary for each
> table to have a primary key. Can anyone shed some light on this for
> me??
>
> Thanks in advance
>
> Lisa
Received on Fri Jun 06 1997 - 00:00:00 CDT