Oracle Message PLS-00153 - A string type may only be used as an object type attribute.

ERRORA string type may only be used as an object type attribute.
CAUSEA POINTER or [SIGNED/UNSIGNED] BINARY INTEGER can only be used as attributes of object types. These types can only be referenced in CREATE TYPE statements, and are non-queryable data types. One of these external PL/SQL types outside of an object type.
ACTIONNone