If, when you come to remove an Oracle database, you find that DBCA is not available perhaps due to some installation issue or missing files then do not fret as it is still possible to remove the database by following these steps…
1 – Set the Oracle SID
D:\Oracle\product\11.2.0\dbhome_1\BIN>set ORACLE_SID=TESTDB
2 – Connect to the database and verify the name
D:\Oracle\product\11.2.0\dbhome_1\BIN>sqlplus / as sysdba SQL*Plus: Release 11.2.0.2.0 Production on Fri Nov 25 09:38:04 2016 Copyright (c) 1982, 2010, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> select name from v$database; NAME --------- TESTDB
3 – Shutdown the database
SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down.
4 – Startup the database in exclusive mode
SQL> startup mount exclusive restrict ORACLE instance started. Total System Global Area 2137886720 bytes Fixed Size 2254896 bytes Variable Size 1577060304 bytes Database Buffers 553648128 bytes Redo Buffers 4923392 bytes Database mounted.
5 – Drop the database
SQL> drop database; Database dropped. Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64 bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options
You can now check that the database has been dropped by checking that the database files have been removed. Check also that the services have been removed, if they are still listed then you can open a DOS prompt with administrator privileges and then use sc delete <service name>.