Perhaps that would be a better way of putting it.
RF
Robert G. Freeman - Oracle OCP
Oracle Database Architect
CSX Midtier Database Administration
Author
Oracle9i RMAN Backup and Recovery (Oracle Press - Oct 2002)
Oracle9i New Features (Oracle Press)
Mastering Oracle8i (Sybex)
Clark Griswold:
Well, that depends on if the FK is enforced or not too. There should be
minimal
performance impact with an unenforced FK with regards to inserts.
In a DW FK's are often present but not enforced. Unenforced FK's in DW's are
used for a number of reasons, query rewrite among them.
Some of the old
Terrible expecially on inserts into the database, it may have to do a full
table scan to insert one record. Don't do it.
From: Shishir Kumar Mishra [EMAIL PROTECTED]
Reply-To: [EMAIL PROTECTED]
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Subject: Unindexed foreign key
Date:
Whenever You Modify the Parent Table rows the Child Table is Entirely
Locked so that no DML Takes Place.
Also If there are no Indexes on the FK. Oracle Will have to do a FTS for
all the Quries that you are going to Join with the Parent Table.
HTH
Best Regards,
Ganesh R
Tel : +971 (4) 397
Title: RE: Unindexed foreign key
Shishir,
If there are only a few records in the table, very little. However, if the table is nicely populated, it can make a tremendous difference. You could always do a little testing to find out in your particular case, but I wouldn't bother. I ALWAYS
