title: MS Access automatically fill id in main form when data is entered in subform
body: <p>In MS Access, I have an unusual relationship set up.  I am showing coordinates of points in a series of polygons.  The polygons don't need any reference data other than an id, but they can each have any number of coordinates.  So I have two tables: Coordinates and Polygons.  Coordinates has fields: coordinateID, x, y, order, PolygonID.  Polygons just has the PolygonID field which is autonumber.</p>
  
  <pre><code>Polygons                      Coordinates
  --------                      -----------
  PolygonID(primary key)--------PolygonID(foreign key)
                                coordinateID(primary key)
                                x
                                y
                                order
  </code></pre>
  
  <p>I've created a form for Polygons with a subform for Coordinates.  I've set up a parent child relationship with referential integrity.</p>
  
  <p>The problem is, Access normally expects the parent table to have some data other than an autonumber field, so it waits for data entry before creating the next record.  I can type the next number in the sequence, and Access creates the record, but if I skip that step and just enter data in the subform, no record is created in the parent table, and I end up with orphaned entries.  </p>
  
  <p>Is there a way to force Access to create the parent record when I start entering data in the child table?</p>