Re: Index and foreign key

Hey VC!

If you check out the Oracle press materials on Oracle 9i, it explicitly states that dead-locks are checked for and prevented. I guess they made fools out of themselves by point out at something they forgot to implement :-)

Either way, I hope MySQL, DB/2 and Oracle continue to remain in business and keep pushing each other to their limits. MySQL because its included for free with Linux, DB/2 because it maintains some degree of compatibility with Oracle, and Oracle because we've been spending so much time and effort on it.

Anyway, I'd better get going.

Cheers,
NicK

VC wrote:
> 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
>>
>>