How to Drop Database in Oracle 10g?

connect to database as sysdba user
$sqlplus /nolog

SQL>conn sys/@connectionstring as sysdba
Ex: SQL>conn sys/sys123@oradb as sysdba

SQL> shutdown immediate;
oracle database closed
oracle database dismounted
oracle instance shutdown

Start the database to restrict mode
SQL> startup restrict mount;
or
SQL>startup mount exclusive restrict;

Confirm the database name before dropping.
SQL> select name from v$database;
NAME
---------
ORADB

SQL> drop database;
Database dropped

Just check the alertlog file what are the files deleted.

This will drop only database physical files not trace file parameter files.