create table db_space_hist (
	timestamp    date,
	total_space  number(8),
	used_space   number(8),
	free_space   number(8),
        pct_inuse    number(5,2),
        num_db_files number(5)
)
tablespace users;



create or replace procedure db_space_hist_proc as
begin
   -- Delete old records...
   delete from db_space_hist where timestamp > SYSDATE + 364;
   -- Insert current utilization values...
   insert into db_space_hist 
	select sysdate, total_space,
	       total_space-nvl(free_space,0) used_space,
	       nvl(free_space,0) free_space,
	       ((total_space - nvl(free_space,0)) / total_space)*100 pct_inuse,
	       num_db_files
	from ( select sum(bytes)/1024/1024 free_space
	       from   sys.DBA_FREE_SPACE ) FREE,
	     ( select sum(bytes)/1024/1024 total_space,
	              count(*) num_db_files
	       from   sys.DBA_DATA_FILES) FULL;
   commit;
end;
/

show errors



begin
 dbms_scheduler.create_job(
    job_name        => 'tablespace_history',
    job_type        => 'PLSQL_BLOCK',
    job_action      => 'begin db_space_hist_proc; end;',
    start_date      =>  SYSTIMESTAMP,
    repeat_interval => 'freq=weekly; byday=sun',
    end_date        => null,
    enabled         => TRUE,
    comments        => 'Job storing the statistics about database space to db_space_hist table ');
end;


Running the job:
BEGIN
DBMS_SCHEDULER.run_job (job_name => 'tablespace_history');
END;