DATAFILE RESIZE

set pages 999 lines 300

select file_id,FILE_NAME,(BYTES/1024/1024) "Size MB",tablespace_name from dba_data_files where tablespace_name like '%%';

alter database datafile <no.> resize 1024m;

or

SET LONG 90000

select DBMS_METADATA.GET_DDL('TABLESPACE','tablespacename') FROM DUAL;

CREATE TABLESPACE "tablespacename" DATAFILE '/path/filename' SIZE 1024 AUTOEXTEND ON NEXT 512 MAXSIZE 512

ALTER DATABASE DATAFILE <no.> AUTOEXTEND ON NEXT 512 MAXSIZE 3000M;