16.20 - Primary Keys and Primary Indexes - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantageâ„¢ SQL Fundamentals

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Published
March 2019
Language
English (United States)
Last Update
2019-05-02
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The following table summarizes the differences between keys and indexes, using the primary key and primary index for purposes of comparison.

Primary Key Primary Index
Important element of logical data model. Not used in logical data model.
Used to maintain referential integrity. Used to distribute and retrieve data.
Must be unique to identify each row. Can be unique or nonunique.
Values cannot change. Values can change.
Cannot be null. Can be null.
Does not imply access path. Defines the most common access path.
Not required for physical table definition. Required for physical table definition.