Oracle Message PLS-00315 - Implementation restriction: unsupported table index type

ERRORImplementation restriction: unsupported table index type
CAUSEIn the INDEX BY clause of a PL/SQL table declaration, a datatype other than BINARY_INTEGER, PLS_INTEGER, or VARCHAR2 was specified. PL/SQL tables can have one column and a primary key. The column can have any scalar type, but the primary key must be either a binary integer type or VARCHAR2.
ACTIONUse one of the supported key types in the INDEX BY clause.