Re: Index and foreign key

Hello Olivier,

Unindexed foreign keys can cause a dead-lock during concurrent primary keys updates/deletes under any current Oracle version including 9i. I'd be very much impressed if this problem were fixed in 10g...

So if you anticipate updates/deletes to the primary key, the foreign keys have to be indexed.

Also, an unindexed foreign key is a performance issue if:

• you have an 'on delete cascade'; -- you query from the parent table to the child table;

Rgds.

VC

"Olivier Crèvecoeur" <Olivier.Crevecoeur_at_ulg.ac.be> wrote in message news:brsfea$1eom_at_aix4.segi.ulg.ac.be...
> Hello,
>
> Excuse me for my poor english.
> I would kike know if create index on the foreign key it's necessary or if
> Oracle, are optimized for using foreign key whithout index.
>
> Best regards
>
> Olivier
>
>
Received on Thu Dec 18 2003 - 23:36:49 CET