alter database datafile maxsize 32g

1SELECT * FROM DBA_DATA_FILES;
2
3ALTER TABLESPACE my_tbs ADD DATAFILE '/path/to/my_file.dbf' 
4	SIZE 100M AUTOEXTEND OFF;
5-- Autoextend with max size:
6ALTER TABLESPACE my_tbs ADD DATAFILE '/path/to/my_file.dbf' 
7	SIZE 10G AUTOEXTEND ON NEXT 1G MAXSIZE 32G;    
8-- For TEMP tablespaces:
9ALTER TABLESPACE my_tbs ADD TEMPFILE '/path/to/my_file.dbf' 
10	SIZE 100M AUTOEXTEND OFF;