Undo tablespace datafile has been corrupted or had been deleted by sysadmin.
Database was properly shutdown i.e. no active rollback segment exists
Location of Undo Tablespace
Undo Tablespace is corrupted and sysadmin deleted the undo file, no backup of undo file exists
SQL> shutdown immediate;
ORACLE instance shut down.
ORACLE instance started.
Total System Global Area 535662592 bytes
Fixed Size 1385840 bytes
Variable Size 297798288 bytes
Database Buffers 230686720 bytes
Redo Buffers 5791744 bytes
ORA-01157: cannot identify/lock data file 3 – see DBWR trac...Read More