hi steve.Thanks a lot.
what i want to know is that if i add child link field and master link field to id i hope it is not necessary to have the id field on the subform also.

Post followup messages back in the same topic you started earlier, otherwise people will get confused. Rich and Pat answered your question in your original topic, located here: http://www.access-programmers.co.uk/ubb/Forum3/HTML/002748.html

David R