Drop database including Rman backups in oracle

Example -  Deleting a Database
 
In this example, you want to delete a test database called test1 that is registered in the recovery catalog. You start the RMAN client, connect to database test1 as TARGET, and connect to the recovery catalog. You then run the following commands to delete the target database files, as well as all backups, copies, and archived logs associated with the database:

RMAN> CONNECT TARGET SYS@test1

target database Password: password
connected to target database: TEST1 (DBID=3952556153453)

RMAN> STARTUP FORCE MOUNT

RMAN> SQL 'ALTER SYSTEM ENABLE RESTRICTED SESSION';

RMAN> DROP DATABASE INCLUDING BACKUPS NOPROMPT;