Oracle Solution for Error ora-12036

ORA-12036: updatable materialized view log is not empty, refresh materialized view

What triggered the Error:

The updatable materialized view log was not empty. The updatable materialized view log must be empty before an updatable rowid materialized view can be altered to a primary key materialized view.

What should we do to fix it:

Ensure that updatable materialized view log is empty by refreshing the materialized view before converting the updatable ROWID materialized view to a primary key materialized view.