From: boston103@hotmail.com   
      
   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   
   >   
   >   
      
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