Update child form with stateless form?

Update child form with stateless form?

Hi there

I have a parent form "Booking" which contains a "Date Booking Made" field.

I have a child form "Booking Detail" which contains a "Booking Date" field - this field was added today.

I need to find a way to update this "Booking Date" field to match the "Date Booking Made" field on the parent. 

If it helps, the "Date Booking Made" is the same as the date for the timestamp of adding the record.  The "Date Booked" field is also that same date.

I've tried this but it didn't work.

  1. for each line in Booking_Detail  [(ID is not null)]
  2. {
  3.     update = Booking[ID == line.Booking_Header_ID].Date_Booking_Made;
  4.     line.Booking_Date = update;
  5. }


Thanks
Aaron