I have mistakenly added datafile to the tablespace... And was trying to drop it. I run the following:
alter database datafile 'datafile_name' OFFLINE;
now when I run
alter database datafile 'datafile_name' ONLINE;
it shows
ORA-01113: file 30 needs media recovery
ORA-01110: data file 30: 'datafile_name'
also status of the file is RECOVER... What can I do? I cant restart database....