16.20 - Keys - 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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A primary key is a column, or combination of columns, in a table that uniquely identifies each row in the table. The values defining a primary key for a table:

  • Must be unique
  • Cannot change
  • Cannot be null

A foreign key is a column, or combination of columns, in a table that is also the primary key in one or more additional tables in the same database. Foreign keys provide a mechanism to link related tables based on key values.