Where Have My Data Gone? Source DB doesn't get updated...

[Sonhospa]

Hi all, I hope I can find someone with a deeper insight regarding LINQ here... In my sample application I add some records to a DataContext and update others. Querying the DataContext afterwards retrieves the changed / added records properly – while checking the data in the underlying database (in ServerExplorer) shows the old DB status without any changes / additions. Can someone pls tell me how I finally get the newer data written into the underlying database? Thank you for any helpful ideas! Here's the (VB) code I use:

Public Class MyMainApp
Public Shared Sub main(ByVal args() As String)
Dim db As New PharaoDataContext

    db.QueryProducts()              ' query all records
    InsertTest(db)
    UpdateProducts(db)
    db.QueryProducts()              ' query again and wait for input

    Console.ReadLine()
    db.Dispose()
End Sub

Public Shared Sub InsertTest(ByRef db As PharaoDataContext)

    Dim cust As New Customer
    With cust
        .First\_Name = "Paul"
        .Last\_Name = "Miller"
    End With
    db.Customer.InsertOnSubmit(cust)

    Dim item1 As New Item
    With item1
        .Item\_Name = "DVD"
        .Item\_Price = 19.75
    End With
    db.Item.InsertOnSubmit(item1)

    Dim item2 As New Item
    With item2
        .Item\_Name = "BlueRay"
        .Item\_Price = 29.75
    End With
    db.Item.InsertOnSubmit(item2)

    ' for debugging: print changes to screen
    Dim mySet As System.Data.Linq.ChangeSet = db.GetChangeSet()
    Dim liste As Object = mySet.Inserts

    For Each entry As Object In liste
        Select Case True
            Case TypeOf (entry) Is Item
                Console.WriteLine(entry.Item\_Name)
            Case TypeOf (entry) Is Customer
                Console.WriteLine(entry.last\_name)
            Case Else
                Console.WriteLine("Objekt vom Typ '{0}'", entry.GetType.Name)
        End Select

    Next

    db.SubmitChanges()               '<---- doesn't seem to update the DB

End Sub

Public Shared Sub UpdateProducts(ByRef db As PharaoDataContext)
    Dim query = db.Item.SingleOrDefault(Function(it) it.ItemID = 2)

    If query IsNot Nothing Then
        Console.Write("Change '{0}' to ", query.Item\_Name)
        query.Item\_Name = Console.ReadLine()
        db.SubmitChanges()