16.20 - Difference Between CREATE CAST and REPLACE CAST - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Detailed Topics

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Release Date
March 2019
Content Type
Programming Reference
Publication ID
B035-1184-162K
Language
English (United States)

To perform a CREATE CAST statement, a user-defined cast that performs the same conversion cannot exist or the statement returns an error to the requestor.

IF you perform a REPLACE CAST statement and there is … THEN the system …
no existing user-defined cast that performs the specified conversion creates a new user-defined cast.

The result is the same as if you had performed a CREATE CAST statement with all the same specifications.

an existing user-defined cast that performs the specified conversion replaces the existing user-defined cast definition with the newly defined cast routine.

If the cast routine is a method, then that method must be already be defined or the system returns an error to the requestor and does not register the method for casting.