UDF usage is restricted as follows:
- If the UDF library for your database contains any objects with multibyte characters in their name, you cannot use a single-byte session character set to create a new UDF, UDT, method, or Java external procedure object even if the new object name contains only single-byte characters. Instead, use a multibyte session character set.
- You cannot perform a CREATE FUNCTION or REPLACE FUNCTION request from an embedded SQL application.
- A UDF cannot reference a recursive view.
- A row-level security policy can only be a scalar function.
- You cannot call a row-level security policy function from a DML request.
Row-level security policy UDFs can only be specified for columns in a CREATE TABLE or ALTER TABLE request.
- Non-Java UDFs can specify both distinct and structured UDTs as input and return parameters.
- If you specify a UDT as either an input parameter or as the function result, the current user of the function must have either the UDTUSAGE privilege on the SYSUDTLIB database or the UDTUSAGE privilege on the specified UDT.
- UDFs that are used as cast routines, ordering routines, or transform routines must be contained within the SYSUDTLIB database.
- Java UDFs cannot be called from within a Java external procedure.
- Any nondeterministic elements referenced in the RETURN expression of a UDF can be replaced by values predefined by Teradata Unity. For more information about Teradata Unity, see the Teradata Unity documentation.