Oracle database to manually enlarge the table space

1. First look at the name of the tablespace and the file you belong to
Select Tablespace_name, file_id, file_name,
Round (bytes/(1024*1024), 0) Total_space
From Dba_data_files
Order BY Tablespace_name;

2. Additional Data files

Alter tablespace users add datafile '/u01/oracle/oradata/umail/users02.dbf ' size 4000M autoextend off;
ALTER DATABASE datafile '/U01/ORACLE/ORADATA/UMAIL/USER01.DBF ' autoextend off;

3. View table space Information after setting
SELECT a.tablespace_name,a.bytes total,b.bytes USED, c.bytes free,
(b.bytes*100)/a.bytes "% USED", (c.bytes*100)/a.bytes "% free"
From SYS. Sm$ts_avail A,sys. Sm$ts_used B,sys. Sm$ts_free C
WHERE A.tablespace_name=b.tablespace_name and A.tablespace_name=c.tablespace_name;