数据库打开阶段，新增的数据文件损坏

SQL> conn test/oracle_4U
Connected.
SQL> create table testdat tablespace testdat as select * from all_objects;


Table created.


SQL> !rm /oradata/ORCL/datafile/testdat.dbf


SQL> conn / as sysdba
Connected.
SQL> alter system flush buffer_cache;


System altered.


SQL> select count(*) from test.testdat;
select count(*) from test.testdat
                          *
ERROR at line 1:
ORA-01116: error in opening database file 5
ORA-01110: data file 5: '/oradata/ORCL/datafile/testdat.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3




SQL> recover datafile 5;
ORA-00283: recovery session canceled due to errors
ORA-01124: cannot recover data file 5 - file is in use or recovery
ORA-01110: data file 5: '/oradata/ORCL/datafile/testdat.dbf'




SQL> alter tablespace testdat offline immediate;


Tablespace altered.


SQL> alter database create datafile '/oradata/ORCL/datafile/testdat.dbf';


Database altered.


SQL> recover datafile 5;
Media recovery complete.
SQL> alter tablespace testdat online;


Tablespace altered.


SQL> select count (*) from test.testdat;


  COUNT(*)
----------
     68308