16.10 - Unique Indexes - Teradata Database

Teradata Database SQL Fundamentals

Product
Teradata Database
Release Number
16.10
Release Date
June 2017
Content Type
Programming Reference
Publication ID
B035-1141-161K
Language
English (United States)

A unique index, like a primary key, has a unique value for each row in a table.

Teradata Database defines two different unique indexes:

  • Unique primary index (UPI)

    UPIs provide optimal data distribution and are typically assigned to the primary key for a table. When a NUPI makes better sense for a table, then the primary key is frequently assigned to be a USI.

  • Unique secondary index (USI)

    USIs guarantee that each complete index value is unique, while ensuring that data access based on it is always a two-AMP operation.