ORA-01078 When running Dbca Delete Database

When trying to delete a database by running dbca, the following errors appear:

$  dbca  -silent -deleteDatabase -sourceDB TESTDB -sysDBAUserName sys  -sysDBAPassword "sys_password"
ORA-01078: failure in processing system parameters

SOLUTION

Remove the entry in /etc/oratab for this database to be deleted.
Make sure here sourceDB name is actually UNIQUE_DB_NAME, instead of DB_NAME.

$  dbca  -silent -deleteDatabase -sourceDB TESTDB_UQ sysDBAUserName sys  -sysDBAPassword "sys_password"
Connecting to database
9% complete
14% complete
19% complete
23% complete
28% complete
33% complete
38% complete
47% complete
Updating network configuration files
48% complete
52% complete
Deleting instances and datafiles
66% complete
80% complete
95% complete
100% complete
Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/TESTDB.log" for further details.