Oracle Error PLS-00646: MAP or ORDER method must be defined in the root of the subtype hierarchy

Oracle Error Message

PLS-00646: MAP or ORDER method must be defined in the root of the subtype hierarchy

Reason for the Error

An attempt was made to define a MAP or ORDER method in a subtype.

Solution

Define the MAP or ORDER method in the root of the subtype hierarchy. You can override MAP methods in subtypes.