Oracle -- Importing Database Recovery Catalog

To merge two recovery catalogs, one from the 10.2 release and the other from 11g, into a single 11g
release catalog schema. 

This is also helpful importing production catalog information  into dr catalog  

1. Connect to the destination recovery catalog.

$ rman

RMAN> connect catalog rman/rman@rman11

2. Issue the IMPORT CATALOG command connecting to source recovery catalog 

RMAN> import catalog rman1/rman1@rman10;

To specify which database to register:

RMAN> import catalog rman10/rman10@tenner dbid = 123456, 1234557;

RMAN> import catalog rman10/rman10@tenner db_name = testdb, mydb;

-- by default, the databases are unregistered from the source catalog:

RMAN> import catalog rman10/rman10@tenner NO UNREGISTER

3. Validate after import 

RMAN> list db_unique_name all