After you shutting down an Oracle database, you accidentally deleted a data file from the operating system. If you try to start the database again you will get error when Oracle tries to open the database after mounting the database. The following tutorial examples shows you what will happen if the data file c: empmy_space.dbf is deleted. Oracle can still start the database instance and mount the database. But it will fail on opening the database as shown below in a SQL*Plus session:

>sqlplus /nolog

SQL> connect SYSTEM/globalguideline AS SYSDBA

SQL> STARTUP

ORACLE instance started.

Total System Global Area 100663296 bytes

Fixed Size   1285956 bytes

Variable Size   58720444 bytes

Database Buffers   37748736 bytes

Redo Buffers   2908160 bytes

Database mounted.

ORA-01157: cannot identify/lock data file 5 - see DBWR

trace file

ORA-01110: data file 5: 'C:TEMPMY_SPACE.DBF'

SQL> SHUTDOWN;

ORA-01109: database not open

Database dismounted.

ORACLE instance shut down.