SQL> create tablespace maclean datafile size 10M;
Tablespace created.
SQL> alter tablespace maclean add datafile size 10M;
Tablespace altered.
SQL> alter tablespace maclean add datafile size 10M;
Tablespace altered.
SQL> select name,file# from v$DATAFILE;
NAME FILE#
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C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_SYSTEM_6VWCSPD4_.DBF 1
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_SYSAUX_6VWCT4N3_.DBF 2
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_UNDOTBS1_6VWCTGK4_.DBF 3
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_USERS_6VWCV01L_.DBF 4
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_UI_6YW3OX2J_.DBF 5
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_TOO_MANY_70679V7W_.DBF 6
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_ASSFDS_7088L5MF_.DBF 7
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_SYSTEM_70PLM9PB_.DBF 8
C:\SS.DBF 9
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_MACLEAN_7CBQ9RLD_.DBF 10
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_MACLEAN_7CBQBJXK_.DBF 11
C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_MACLEAN_7CBQBLQR_.DBF 12
12 rows selected.
SQL> create table extend_on_datafile12 (t1 int) tablespace maclean;
Table created.
SQL> alter table extend_on_datafile12 allocate extent ( datafile 'C:\APP\ORADATA\G11R2\DATAFILE\O1_MF_MACLEAN_7CBQBLQR_.DBF' size 2M);
Table altered.
SQL> select file_id from dba_extents where segment_name='EXTEND_ON_DATAFILE12';
FILE_ID
----------
12
12
12