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Question and Answer

Connor McDonald

Thanks for the question, Ali.

Asked: January 17, 2017 - 10:43 am UTC

Last updated: January 19, 2017 - 1:04 am UTC

Version: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0

Viewed 1000+ times

You Asked

Hello,

I am refactoring and existing dB. No primary key and indexes were used.

There will be surrogate numeric (integer) primary keys on new tables with foreign key constraints...

I was wondering what is the best numeric format for performances?

By default, I see PK as NUMBER (no precision).

Shall I add a precision for better performance on Indexes? If yes, which one?

I saw on some posts Number(38,0) or even Number (9,0) to match INT32...

Thanks in advance for your answers,
Ali

PS: you may point to an article/post on performances and indexes in oracle for my knowledge ;-)

and Connor said...

I would definitely use NUMBER(n) because otherwise, "123.546223" becomes a valid primary key. In *theory* you wouldn't care, but given that 99% of the world's surrogate keys are probably an integer or guid, there will probably be plenty of developers assuming this and therefore getting in code trouble if its not.


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More on Oracle indexes

Rajeshwaran, Jeyabal, January 18, 2017 - 11:11 am UTC

you may point to an article/post on performances and indexes in oracle for my knowledge ;-)

To learn all about indexes in Oracle database, then richard's blog is the best place to go.

https://richardfoote.wordpress.com/
Connor McDonald
January 19, 2017 - 1:04 am UTC

I agree 100%
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