Using Default Value Control Phrases

Teradata Vantageā„¢ Data Types and Literals

brand
Software
Teradata Vantage
prodname
Teradata Database
Teradata Vantage NewSQL Engine
vrm_release
16.20
category
Programming Reference
featnum
B035-1143-162K

Purpose

A default value control phrase determines the action to take when you do not supply a value for a field.

Rules and Guidelines

The following rules and guidelines apply to default value control phrases:
  • Default value control phrases are only valid with the following data definitions.
    • Fields defined in CREATE TABLE and ALTER TABLE statements
    • Parameters defined in CREATE MACRO and REPLACE MACRO statements
  • Default value controls are not effective for views and expressions.
  • The default value for a field is null unless you specify NOT NULL, in which case there is no default value if you do not specify the DEFAULT phrase.
  • The presence of nulls can affect query performance negatively; therefore, consider using the NOT NULL default value phrase unless you intend to have nulls in the column.

The default control value phrases are documented individually in the remaining topics in this section.