Unique Indexes - Advanced SQL Engine - Teradata Database

SQL Fundamentals

Product
Advanced SQL Engine
Teradata Database
Release Number
17.05
17.00
Published
June 2020
Language
English (United States)
Last Update
2021-01-24
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B035-1141
lifecycle
previous
Product Category
Teradata Vantageâ„¢

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.