pg.ddx.io pgsql-sql@postgresql.org mailing list archive
help / color / mirror / Atom feedUnique key field or serverl fks ?
3+ messages / 2 participants
[nested] [flat]
* Unique key field or serverl fks ?
@ 2004-01-12 05:51 katarn <katarn@racsa.co.cr>
0 siblings, 1 reply; 3+ messages in thread
From: katarn @ 2004-01-12 05:51 UTC (permalink / raw)
To: pgsql-sql
Hi,
I would like to know opinions about which approach is better:
Having a table with a field that works as a unique key, or having
several fks that work as a combined key ( all the fks fields )?
Thanks in advance,
K.
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Unique key field or serverl fks ?
@ 2004-01-12 09:52 Richard Huxton <dev@archonet.com>
parent: katarn <katarn@racsa.co.cr>
0 siblings, 1 reply; 3+ messages in thread
From: Richard Huxton @ 2004-01-12 09:52 UTC (permalink / raw)
To: katarn <katarn@racsa.co.cr>; pgsql-sql
On Monday 12 January 2004 05:51, katarn wrote:
> Hi,
>
> I would like to know opinions about which approach is better:
>
> Having a table with a field that works as a unique key, or having
> several fks that work as a combined key ( all the fks fields )?
Depends on the particular situation, you'll need to give details of the tables
and their place in your system.
There are two reasons I've seen given for using an artificial (substitute)
primary key:
1. It's "lighter" than several other fields (especially where they are text)
2. The natural primary key has meaning to the users, and the users will tend
to get it wrong.
The second is probably the more persuasive - the first can definitely have
costs as well as benefits.
--
Richard Huxton
Archonet Ltd
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Unique key field or serverl fks ?
@ 2004-01-12 21:36 katarn <katarn@racsa.co.cr>
parent: Richard Huxton <dev@archonet.com>
0 siblings, 0 replies; 3+ messages in thread
From: katarn @ 2004-01-12 21:36 UTC (permalink / raw)
To: pgsql-sql
>>Hi,
>>
>>I would like to know opinions about which approach is better:
>>
>>Having a table with a field that works as a unique key, or having
>>several fks that work as a combined key ( all the fks fields )?
>>
>>
>
>Depends on the particular situation, you'll need to give details of the tables
>and their place in your system.
>
>There are two reasons I've seen given for using an artificial (substitute)
>primary key:
>1. It's "lighter" than several other fields (especially where they are text)
>2. The natural primary key has meaning to the users, and the users will tend
>to get it wrong.
>
>The second is probably the more persuasive - the first can definitely have
>costs as well as benefits.
>
>
>
Ok, thanks for answering, example:
Articles Table
articleid
Warehouses Table
warehouseid
Locations per warehouse Table
warehouseid (fk)
locationid
description
Articles Per warehouse
warehouseid (fk)
articleid (fk)
locationid (fk)
stock
In the Articles per warehouse the "primary key" is the cominbation of 3
fks. Is that kind of situation acceptable or it could be better to have
a unique primary key field in addition to the fks? This "gets worse" if
another table has information binded to the articles per warehouse, it
has to reference the 3 fks in addition to its own key fields.
Thanks in advance,
K.
^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2004-01-12 21:36 UTC | newest]
Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2004-01-12 05:51 Unique key field or serverl fks ? katarn <katarn@racsa.co.cr>
2004-01-12 09:52 ` Richard Huxton <dev@archonet.com>
2004-01-12 21:36 ` katarn <katarn@racsa.co.cr>
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox