The result predefined data type returned by the external function that is to be converted to the type specified by the RETURNS clause.
...RETURNS DECIMAL(9,5) CAST FROM FLOAT...
You cannot specify a character server data set of KANJI1. Otherwise, the system returns an error to the requestor.
Whenever a LOB that requires data type conversion is passed to a method, the LOB must first be materialized for the conversion to occur.