oem12c 2-system upgrade .. need for "Link the earlier release of the Management Repository with the
After you upgrade the Management Repository in the backed up database, link it to your earlier release of the Management Repository so that the two repositories are linked with each other, and any operations on the upgraded repository can be directly done from old repository.
I am still NOT sure of what type of operations need this db link ? what is the purpose of this db link ? could somebody elaborate on this ?