Home Page for the TeradataForum

Archives of the TeradataForum

Message Posted: Wed, 29 Oct 2015 @ 00:37:31 GMT

  <Prev Next>   <<First <Prev Next> Last>>  

Subj:   Re: SET vs MULTISET tables with UPI/USI
From:   Pluebell, Fred

The duplicate row checking is still done, but with a UPI you only have to check at most one row so the overhead is tiny. With NUPI, the overhead can be substantial even with a USI.

If you have a SET table with a UPI or USI, then multiple-row operations (e.g. INSERT SELECT or MERGE) will quietly eliminate duplicate rows , whereas with MULTISET table and UPI or USI, the duplicate key check will cause the operation to fail. For single-row operations (e.g. INSERT VALUES), SET/MULTISET both give duplicate key error.

  <Prev Next>   <<First <Prev Next> Last>>  
  Top Home Privacy Feedback  
Copyright for the TeradataForum (TDATA-L), Manta BlueSky    
Copyright 2016 - All Rights Reserved    
Last Modified: 24 Jul 2020