Performance impacts using Unique Keys vs Primary Keys [message #21647] |
Wed, 21 August 2002 07:54 |
Malini K. Sinha
Messages: 4 Registered: July 2002
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From a logical standpoint, a Primary Key (PK) is a Unique Key (UK) with a "Not Null" constraint on the respective column(s).
However, while performing joins within SELECTs, does Oracle 8i's Cost Based Optimizer cause any performance impacts that would cause me to choose using a PK instead of a UK with a "Not Null" constraint?
Also, is there any impact while using Triggers with a UK with a "Not Null" constraint?
I know Oracle 7i had a performance impact as a result of using a UK with a "Not Null" constraint, but not sure if Oracle 8i fixed this.
Can anybody help me with this?
Thanks in advance.
Malini
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