Read your file, move the data to the subfile record. when either the page is built or the subfile is loaded you would execute the subfile control record. If you are looking to do this in a different way we need more details. in you tags you list SQL. You may want to extract the data like this and read from that file.
C+ DECLARE OHB CURSOR FOR
C+ SELECT OHORD#, OHBTKY, OHSPO#, OHENTD, OHHOLD, OHFF3, OHSM
C+ FROM OH
C+ WHERE OHHOLD = 'E' AND OHFF3 <> ' ' AND OHBTKY = :INCUST
C+ AND OHPRKY <> 'DADANC'
C+ OPEN OHB