Before you upgrade, each effective period of a relationship has a dedicated base object record. The upgrade process creates a cross-reference record for each effective period. The upgrade process merges the base object records for each relationship into a single record. The MDM Hub uses the HM_MIG tag in the ROWID_MATCH_RULE column of the HMRG table to track the merged base object records. Do not unmerge these base object records. If you unmerge these relationship base object records, the Hierarchy Manager might display the incorrect effective period for the relationship. Ensure that you assess the impact of the consolidation of hierarchy relationship base objects after the upgrade.

If your database environment is set to a non-English locale, ensure that the character set is a Unicode character set before you upgrade the Hub Store. After the upgrade completes successfully, you can select your preferred locale. The locale is stored as a user account preference, rather than at the database level.