Keywords That Introduce Modifications

Keyword	Effect on Specified Routine Modifier
ADD	Add a new routine modifier to the UDR
MODIFY	Change an attribute of the routine modifier
DROP	Delete the routine modifier from the UDR
MODIFY EXTERNAL NAME (for external functions only)	Replace the file specification of the executable file. When the IFX_EXTEND_ROLE configuration parameter = ON, this option is valid only for users to whom the DBSA has granted the EXTEND role. With IFX_EXTEND_ROLE = OFF (or not set), the UDR owner or the DBA can use this option.
WITH	Introduces all modifications

If the routine modifier is a BOOLEAN value, MODIFY sets the value to be t (equivalent of using the keyword ADD to add the routine modifier). For example, both of the following statements alter the func1 function so that it can be executed in parallel in the context of a parallelizable data query:

ALTER FUNCTION func1 WITH (MODIFY PARALLELIZABLE); 
ALTER FUNCTION func1 WITH (ADD PARALLELIZABLE);