In 10g oracle has introduced the concept of recycle bin one can recover tables that were dropped. When a table is dropped, the column “DROPPED” is marked “YES” in the view user_tables/all/dba_tables.

USER_RECYCLEBIN – This view has dropped objects in current user’s schema

Clean current user’s recycle bin
SQL> purge recyclebin;

Recyclebin purged.

DBA_RECYCLEBIN – Has dropped objects in all users

# purge all tables in the recycle bin
SQL> purge dba_recyclebin;

DBA Recyclebin purged.