How CREATE FUNCTION and REPLACE FUNCTION Differ | VantageCloud Lake - Differences between CREATE FUNCTION and REPLACE FUNCTION for a UDT - Teradata Vantage

A function can be created or replaced using the same syntax except for the keywords CREATE and REPLACE.

If you specify CREATE, the function must not exist.

If you specify REPLACE, you can either create a new function or replace an existing function with the following restriction: if the function to be replaced was originally created with a specific function name, then that specific function name must be used for the REPLACE FUNCTION statement.

When you replace an existing function, the replaced function does not retain the EXECUTE NOT PROTECTED attribute if one had previously been set using the ALTER FUNCTION statement. See When to Specify Unprotected Mode (ALTER FUNCTION External Form).

The advantage to using REPLACE is that you can avoid having to grant the EXECUTE privilege again to all users who already had that privilege on the function.

See the following topics for important restrictions on replacing UDFs that perform UDT-related functionality.

Replacing an Ordering or Transform UDF

Replacing a Casting UDF for a UDT

Trying to replace a casting function using REPLACE FUNCTION is an error.