variable object_number number
variable relative_fno number
variable block_number number
variable row_number number

declare
   oe_rownum    rowid;
   rowid_type   number;
begin
   select rowid into oe_rownum from oe.arch_orders
     where order_id = 2358 and rownum = 1;
   dbms_rowid.rowid_info (rowid_in => oe_rownum,
     ts_type_in => 'BIGFILE',
     rowid_type => rowid_type,
     object_number => :object_number,
     relative_fno => :relative_fno,
     block_number => :block_number,
     row_number => :row_number);
end;