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   comp.databases.oracle      Overblown overpriced overengineered SHIT      2,288 messages   

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   Message 829 of 2,288   
   NicK to All   
   Re: Index and foreign key   
   19 Dec 03 18:43:38   
   
   From: nospam@emirates.net.ae   
      
   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"  wrote in message   
   > news:brsfea$1eom@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   
   >>   
   >>   
   >   
   >   
   >   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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