This is what I have written down for dropping a database when
you delete the .dbf file first:
connect internal;
startup mount;
alter database datafile "/fullpath/filename.dbf" offline drop;
alter database open;
drop tablespace tablespacename including contents;
but if you don't want to drop the associated tablespace I suspect you
will have to seek guidance from an actual DBA (not a cargo cult DBA
which is what I am).
