RE: To foreign key or not to foreign key
- From: "Lex de Haan" <lex.de.haan@xxxxxxxxxxxxxx>
- To: <fuadar@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 14 Dec 2004 18:20:30 +0100
you are asking two things, right?
all foreign keys (and other constraints) should be declared in the database
-- there is (should be) no discussion about that. period.
whether or not to *index* your foreign keys, that's a different matter.
Indexes slow down DML, and the locking issues with unindexed foreign keys
only occur in certain scenarios, all well documented. having 15 indexed
foreign keys in a demanding OLTP environment does not sound fun to me.
Hope this helps, cheers,
Lex.
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Fuad Arshad
Sent: Tuesday, December 14, 2004 17:34
To: oracle-l@xxxxxxxxxxxxx
Subject: To foreign key or not to foreign key
I know this has been discussed here before and i did find a couple of
jonathan lewis's old posts
The thing is we have a project where the consultants want to ensure about
10-15 foreign keys per tables to enforce parent child relationships.
I've seen locking issues beforer and was wondering if the list could put
down a some pros and cons as to going or not going with a primary foriegn
key strategy.
This is a oltp type system and sub second response is what the enpd product
requires( isnt that the description of every project these days).
The consultants want every foreign key indexed. which i think is way too
much a performance degradation since inserts are going to be major part of
the application.
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