Making Changes to Columns | ALTER TABLE | Teradata Vantage - Changing Column Attributes: NOT NULL or NULL - Analytics Database - Teradata Vantage

SQL Data Definition Language Detailed Topics

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2023-07-11
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dita:id
B035-1184
lifecycle
latest
Product Category
Teradata Vantage™

When changing columns from NULL to NOT NULL, or from NOT NULL to NULL, refer to the following table.

Column Attribute Composite Changes
NULL Not permitted.
NOT NULL Permitted.

The following rules define how columns defined with NULL or NOT NULL attributes can be altered.

This column type … When defined as … Can be altered to this column type …
Indexed NULL NULL only
NOT NULL NOT NULL only
Unindexed NULL NOT NULL

If and only if the column does not contain nulls.

NOT NULL NULL