15.00 - Unique Primary Indexes - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

Unique Primary Indexes

Major entities and subentities are typically assigned unique primary indexes. When a subentity has been defined in the logical model, it typically uses the same unique primary index in the physical model as the major entity it is associated with. This ensures that related rows from the two tables always hash to the same AMP.

Consider the following employee table derived from a major entity in the logical database design. The primary key is also defined as the unique primary index for the table.

 

You should always specify the unique primary index column set as NOT NULL.