Taking the datafile offline when the database is in NOARCHIVELOG mode

Question

My question is when the database is in No Archive log mode i'm not able to take the datafile offline.
When i tried in my computer i have noticed fallowing.
case1:
SYS>alter database datafile 5 offline;
ERROR at line1;
ORA-01145:offline immediate disallowed unless media recovery enabled.
case 2:
SYS>alter database datafile 5 offline immediate;
ERROR at line 1;
ORA-00933:SQL command not properly ended
case3:
I have tried the command alter database datafile 6 offline drop; (in NOARCHIVELOG mode) and it is showing the same effect as alter database datafile 6 offline; ( in ARCHIVELOG mode).
*In the NOARCHIVELOG mode are we really dropping the datafile to take the datafile offline? Will you please tell me the effect of keyword drop.

Answer 1

JohnWatson wrote:
You've marked your question answered - was that a mistake?
The answer is that you cannot directly take a datafile offline in noarchivelog mode. You must take the tablespace offline:
Hmm, are you certain about that? Perhaps I'm missing something.
SQL> select file_id, file_name, online_status, status from dba_data_files where tablespace_name = 'USERS';
   FILE_ID FILE_NAME                                          ONLINE_ STATUS
         4 /u01/app/oracle/oradata/TEST/users01.dbf           ONLINE  AVAILABLE
SQL> select log_mode from v$database;
LOG_MODE
NOARCHIVELOG
SQL> alter database datafile 4 offline drop;
Database altered.
SQL> select file_id, file_name, online_status, status from dba_data_files where tablespace_name = 'USERS';
   FILE_ID FILE_NAME                                          ONLINE_ STATUS
         4 /u01/app/oracle/oradata/TEST/users01.dbf           RECOVER AVAILABLE
SQL>  ALTER SYSTEM FLUSH BUFFER_CACHE;  <-- may not have been necessary
System altered.
SQL> select count(*) from scott.emp;
select count(*) from scott.emp
ERROR at line 1:
ORA-00376: file 4 cannot be read at this time
ORA-01110: data file 4: '/u01/app/oracle/oradata/TEST/users01.dbf'
SQL> recover datafile 4;
Media recovery complete.
SQL> select file_id, file_name, online_status, status from dba_data_files where tablespace_name = 'USERS';
   FILE_ID FILE_NAME                                          ONLINE_ STATUS
         4 /u01/app/oracle/oradata/TEST/users01.dbf           OFFLINE AVAILABLE
SQL> alter database datafile 4 online;
Database altered.
SQL> select file_id, file_name, online_status, status from dba_data_files where tablespace_name = 'USERS';
   FILE_ID FILE_NAME                                          ONLINE_ STATUS
         4 /u01/app/oracle/oradata/TEST/users01.dbf           ONLINE  AVAILABLE
SQL> select count(*) from scott.emp;
  COUNT(*)
        14
Also, please see the following link from the manual which discusses altering data file availability in noarchivelog mode.
Altering Datafile Availability