I have mistakenly deleted Datafiles.
Since you don't care about the data, you can try the following which will offline and drop the datafile in question allowing you to open the database.

SQL&gt; startup
ORACLE instance started.

Total System Global Area 1720328192 bytes
Fixed Size                  2255904 bytes
Variable Size            1275069408 bytes
Database Buffers          436207616 bytes
Redo Buffers                6795264 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'C:\ORACLE\ORADATA\ORCL\TRASHED01.DBF'

SQL&gt; alter database datafile 6 offline drop;

Database altered.

SQL&gt; alter database open;

Database altered.

SQL&gt;