Change maxsize of datafile .. autoextend on

MAXSIZE (from what I've been reading)is part of the AUTOEXTEND clause.so that instead of simply:MAXSIZE 10000Myou would specify"AUTOEXTEND ON MAXSIZE 10000M"Even though autoextend is already enabled.
------- Syntax ----------
alter database datafile ' datafile ' autoextend on maxsize 1000M;
------- Check ---------------
select file_name,tablespace_name,bytes/1024/1024,autoextensible,maxbytes/1024/1024 from dba_data_files where tablespace_name like '';