Access: A query that resets the autonumbering - ms-access

Question

My database is made for skiing competitions. The idea is that you can fill in the times people ski, and the databse automatically calculates what kind of medal you earned based on someone who set the time first, your gender and your age. I have made a form that makes it able to sign up and give all the results.
The only problem I'm having now is when signing someone up, it must be ordered on age. I did that, but now the autonumbering is all messed up.
What I want is that I can put all the names of the competitors in, and after that I want to have a query which I can choose that assigns all of the starting numbers. Even when the numbers are allready assigned I want to reset it and assign them again if someone joins in lately. I don't want to have to delete the auto numbering field and make it again because most of the time I won't be using it myself but other people will, so I want a simple push on the button that assigns it.
Thanks in advance!
Example how my database and a competition looks like

Answer 1

An Autonumber field is only for identifying records. No more no less.
What you need is a Priority (or Rank) field.
In your form where you display the records, run code like this for that field:
Private Sub Priority_AfterUpdate()
Dim rst As DAO.Recordset
Dim lngId As Long
Dim lngPriorityNew As Long
Dim lngPriorityFix As Long
' Save record.
Me.Dirty = False
' Prepare form.
DoCmd.Hourglass True
Me.Repaint
Me.Painting = False
' Current Id and priority.
lngId = Me!Id.Value
lngPriorityFix = Nz(Me!Priority.Value, 0)
If lngPriorityFix <= 0 Then
lngPriorityFix = 1
Me!Priority.Value = lngPriorityFix
Me.Dirty = False
End If
' Rebuild priority list.
Set rst = Me.RecordsetClone
rst.MoveFirst
While rst.EOF = False
If rst!Id.Value <> lngId Then
lngPriorityNew = lngPriorityNew + 1
If lngPriorityNew = lngPriorityFix Then
' Move this record to next lower priority.
lngPriorityNew = lngPriorityNew + 1
End If
If Nz(rst!Priority.Value, 0) = lngPriorityNew Then
' Priority hasn't changed for this record.
Else
' Assign new priority.
rst.Edit
rst!Priority.Value = lngPriorityNew
rst.Update
End If
End If
rst.MoveNext
Wend
' Reorder form and relocate record.
Me.Requery
Set rst = Me.RecordsetClone
rst.FindFirst "Id = " & lngId & ""
Me.Bookmark = rst.Bookmark
' Present form.
Me.Painting = True
DoCmd.Hourglass False
Set rst = Nothing
End Sub
Just assign a rank to any record, and records will be renumbered as and if needed.