How to fix the Oracle error ORA-23417: unknown materialized view type: string?

In this post, you’ll learn more about the Oracle ErrorORA-23417: unknown materialized view type: string with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-23417: unknown materialized view type: string

Reason for the Error ORA-23417: unknown materialized view type: string

A fast refresh is being performed on a materialized view of an unknown or unsupported type.

How to fix the Error ORA-23417: unknown materialized view type: string ?

You can fix this error in Oracle by following the below steps

Check all_mviews and ensure that the materialized view being refreshed a valid materialized view.