expdp procedure in 11g

 1) create directory export_auto as 'd:\expdp1213';

 create user dba_export_user identified by test123;

grant connect, create database link, resource, create view to dba_export_user;
grant unlimited tablespace to dba_export_user;
grant exp_full_database to dba_export_user;
grant read,write on directory export_auto to dba_export_user;
grant execute on dbms_flashback to dba_export_user;
grant create table to dba_export_user;
grant FLASHBACK ANY TABLE to dba_export_user;


2)
CREATE OR REPLACE PROCEDURE dba_export_user.start_export
IS
   hdl_job        NUMBER;
   l_cur_scn      NUMBER;
   l_job_state    VARCHAR2 (20);
   l_status       SYS.ku$_status1010;
   l_job_status   SYS.ku$_jobstatus1010;
BEGIN

 begin
    execute immediate 'drop table  dba_export_user.AUTO_EXPORT';
    exception when others then null;
   end;

   hdl_job := DBMS_DATAPUMP.OPEN ( operation => 'EXPORT', job_mode => 'FULL', job_name => 'AUTO_EXPORT' );
 
   DBMS_DATAPUMP.add_file (handle => hdl_job,filename => 'EXPDP1213.dmp',directory => 'EXPORT_AUTO',filetype => DBMS_DATAPUMP.ku$_file_type_dump_file,reusefile => 1);
                         
   DBMS_DATAPUMP.add_file (handle => hdl_job,filename => 'export.log',DIRECTORY => 'EXPORT_AUTO',filetype => DBMS_DATAPUMP.ku$_file_type_log_file,reusefile => 1);
                     
   DBMS_DATAPUMP.start_job (handle => hdl_job);
 
   DBMS_DATAPUMP.wait_for_job (handle => hdl_job, job_state => l_job_state);
 
   DBMS_OUTPUT.put_line ('Job exited with status:' || l_job_state);

  DBMS_DATAPUMP.detach(handle => hdl_job);

END;
/


3) Change the time, Date

begin
 dbms_scheduler.create_job(
      job_name => 'EXPORT_JOB'
     ,job_type => 'STORED_PROCEDURE'
     ,job_action => 'dba_export_user.start_export'
     ,start_date => '08-FEB-12 06.02.00.00 PM ASIA/CALCUTTA'
       ,repeat_interval => 'FREQ=DAILY; BYDAY=MON,TUE,WED,THU,FRI,SAT,SUN;'
     ,enabled => TRUE
     ,comments => 'EXPORT_DATABASE_JOB');
end;
/

EXEC  dbms_scheduler.run_job('EXPORT_JOB');