i am getting an error ORA-02291: integrity constraint (RMAN_CATALOG.RLH_F1) violated - parent key no
I unregistered our 12c database in the catalog via RMAN with "unregister database;"
when attempting to re register the database " register database;" I get an error
starting full resync of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03008: error while performing automatic resync of recovery catalog
ORA-02291: integrity constraint (RMAN_CATALOG.RLH_F1) violated - parent key not found
During the resync.
there is a solution
https://coskan.wordpress.com/2009/11/26/ora-02291-integrity-constraint-rman-rlh_f1-violated/
but that looks like something for an 8 or 9 instance.