I'm trying to update a stored value in a table using the following code. It gets the criteria from a subform. It works well when ther is only one field in the subform but only updates the first record when there are multiple rows in the subform. Can anyone take a look at the code and tell me what I'm doing wrong?

Private Sub cmdAddRec_Click()

Dim frm As Form

Set frm = [Forms]![2,3,1 Binnengekomen Bestellingen]

Dim db As Database
Dim rs As DAO.Recordset
Dim strSQL As String

Set db = CurrentDb
strSQL = "SELECT * FROM Artikelen WHERE Artikelnr = &_
""& frm![te verwachten bestelling subform]!Artikelnr & " ;"
Set rs = db.OpenRecordset(strSQL, dbOpenDynaset)

rs.MoveFirst
Do While Not rs.EOF
rs.Edit
rs.Fields("Voorraad").Value = frm![te verwachten bestelling subform]!Aantal + frm![te verwachten bestelling subform]!Voorraad
rs.Update
rs.MoveNext
Loop

rs.Close
Set rs = Nothing
Set db = Nothing

End Sub

you should have posted this in MS Access thread

is this correct
strSQL = "SELECT * FROM Artikelen WHERE Artikelnr = &_
""& frm![te verwachten bestelling subform]!Artikelnr & " ;"
Set rs = db.OpenRecordset(strSQL, dbOpenDynaset)

do you filter a Table "Artikelen" by field "Artikelnr", in this case you will get a recordset with same "Artikelnr" field, and I'm not shure about
frm![te verwachten bestelling subform]!Artikelnr , you get a criterya from the subform, I suppose that you should take criteria from parent form's controll, describe your task more carefully.