Why can we have UPI only when PPI column is part of PI

Database
Enthusiast

Why can we have UPI only when PPI column is part of PI

Why can we have UPI only when PPI column is part of PI, can someone explain in detail?

Thanks in Advance

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3 REPLIES
Enthusiast

Re: Why can we have UPI only when PPI column is part of PI

Any help is appreciated !!

Junior Supporter

Re: Why can we have UPI only when PPI column is part of PI

If the column was not part of the PPI TD should check all and every partition to guarantee unicity, which has a high cost.

That's why. (it's in the manuals, BTW)

Cheers.

Carlos.

Teradata Employee

Re: Why can we have UPI only when PPI column is part of PI

Hi Terasum,

If you really want to check uniqueness in this case, then you can create a USI for the NUPI column(s) for the partitioned table.   This would use the USI index to reduce the high cost which Carlos has explained.

Regards,

Vlad.