Why does TOYS show the underlying tables for materialized views?
A materialized view is implemented by Oracle creating or re-using an underlying table [i.e. container table]. When the container table is prebuilt it has a life cycle that is independent of the materialized view. Container tables that are not prebuilt have the same life cycle as their materialized view. That is, they get implicitly created when the materialized view is created and implicitly dropped when the materialized view is dropped. For comparison purposes, TOYS treats the materialized view and the container table as distinct objects. Thus when the materialized view exists in both the working and reference databases, both the materialized view and the container tables are shown as separate objects. When a materialized view is absent (or extra), the container table is also shown as absent (or extra). TOYS [currently] does not attempt to treat as special, the case where a materialized view exists in one database and not in the other and a table with the same name also does not exist
