以正确的方式更新MVVM模式中的记录以获得最大效率

这更多的是一个概念问题。这是我目前的困境；我正在编写一个vb.net WPF应用程序，并使用MVVM模式（喜欢它！可维护性非常棒）。目前，所有代码都是手工编写的，没有使用NHibernate或实体框架，因为后端是访问数据库（由于策略，我不能使用NH，EF不支持JET数据库，我们可能会在某个时候切换到MSSQL，但这可能需要一段时间）。

该应用程序运行得很好，想知道将更新发送回数据库的最佳方式是什么。

目前的方法是在模型的set部分的记录中添加一个布尔值，使其为"dirty"，然后当按下update时，我们循环遍历所有"dirty（脏）"的记录，并使用oledbcommand（带参数执行）sql语句进行更新。

这创建了一个很好的关注点分离，但如果这是错误的方式，我想知道其他选择（请注意数据库类型和相关的缺点，例如它不适用于EF）。

谢谢！

VB.NET中注释后的最终代码等：

Public Class Car
Implements ICloneable
Public Property Make() As String
    Get
        Return m_Make
    End Get
    Set(ByVal value As String)
        m_Make = value
    End Set
End Property
Private m_Make As String
Public Property Model() As String
    Get
        Return m_Model
    End Get
    Set(ByVal value As String)
        m_Model = value
    End Set
End Property
Private m_Model As String
Public Function Clone() As Object Implements System.ICloneable.Clone
    Return New Car() With { _
     .Make = Me.Make, _
     .Model = Me.Model _
    }
End Function
End Class

Public Class CarEqualityComparer
Implements IEqualityComparer(Of Car)
Public Overloads Function Equals(ByVal x As Car, ByVal y As Car) As Boolean Implements System.Collections.Generic.IEqualityComparer(Of Car).Equals
    Return x.Make = y.Make AndAlso x.Model = y.Model
End Function
Public Overloads Function GetHashCode(ByVal obj As Car) As Integer Implements System.Collections.Generic.IEqualityComparer(Of Car).GetHashCode
    Return 1 'http://blogs.msdn.com/b/jaredpar/archive/2008/06/03/making-equality-easier.aspx
End Function
End Class
Public Class CarRepository
    Private _carComparator As New CarEqualityComparer
    Private _cars As New ChangeTracker(Of Car)(_carComparator)
    Public Function GetCars() As IEnumerable(Of Car)
        'TODO: JET/ADO code here, you would obviously do in a for/while loop
        Dim dbId1 As Integer = 1
        Dim make1 As String = "Ford"
        Dim model1 As String = "Focus"
        Dim dbId2 As Integer = 2
        Dim make2 As String = "Hyundai"
        Dim model2 As String = "Elantra"
        'TODO: create or update car objects
        Dim car1 As Car
        If Not _cars.IsTracking(dbId1) Then
            car1 = New Car()
        Else
            car1 = _cars.GetItem(dbId1)
        End If
        car1.Make = make1
        car1.Model = model1
        If Not _cars.IsTracking(dbId1) Then
            _cars.StartTracking(dbId1, car1)
        End If

        Dim car2 As Car
        If Not _cars.IsTracking(dbId2) Then
            car2 = New Car()
        Else
            car2 = _cars.GetItem(dbId2)
        End If
        car2.Make = make2
        car2.Model = model2
        If Not _cars.IsTracking(dbId2) Then
            _cars.StartTracking(dbId2, car2)
        End If
        Return _cars.GetTrackedItems()
    End Function
    Public Sub SaveCars(ByVal cars As IEnumerable(Of Car))
        'TODO: JET/ADO code here to update the item
        Console.WriteLine("Distinct " & cars.Distinct.Count.ToString)
        For Each changedItem As Car In _cars.GetChangedItems().Intersect(cars)
            Console.Write("Saving: ")
            Console.WriteLine(changedItem.Make)
        Next
        For Each newItem As Car In cars.Except(_cars.GetTrackedItems())
            Console.Write("Adding: ")
            Console.WriteLine(newItem.Make)
            Dim newId As Integer = CInt(Math.Ceiling(Rnd() * 5000)) 'Random right now but JET/ADO to get the id later....
            _cars.StartTracking(newId, newItem)
        Next
        Dim removalArray As New ArrayList
        For Each deletedItem As Car In _cars.GetTrackedItems().Except(cars)
            Console.Write("Removing: ")
            Console.WriteLine(deletedItem.Make)
            removalArray.Add(_cars.GetId(deletedItem)) 'Cannot remove right as iterating through array - clearly that would be problematic....
        Next
        For Each dbId As Integer In removalArray
            _cars.StopTracking(dbId)
        Next
        _cars.SetNewCheckpoint()
    End Sub
End Class
Public Class ChangeTracker(Of T As {ICloneable})
    'item "checkpoints" that are internal to this list
    Private _originals As New Dictionary(Of Integer, T)()
    Private _originalIndex As New Dictionary(Of T, Integer)()
    'the current, live-edited objects
    Private _copies As New Dictionary(Of Integer, T)()
    Private _copyIndex As New Dictionary(Of T, Integer)()
    Private _comparator As System.Collections.Generic.IEqualityComparer(Of T)
    Public Sub New(ByVal comparator As System.Collections.Generic.IEqualityComparer(Of T))
        _comparator = comparator
    End Sub
    Public Function IsChanged(ByVal copy As T) As Boolean
        Dim original = _originals(_copyIndex(copy))
        Return Not _comparator.Equals(copy, original)
    End Function
    Public Function GetChangedItems() As IEnumerable(Of T)
        Dim items As IEnumerable(Of T)
        items = _copies.Values.Where(Function(c) IsChanged(c))
        Return items
    End Function
    Public Function GetTrackedItems() As IEnumerable(Of T)
        Return _copies.Values
    End Function
    Public Sub SetNewCheckpoint()
        For Each copy In Me.GetChangedItems().ToList()
            Dim dbId As Integer = _copyIndex(copy)
            Dim oldOriginal = _originals(dbId)
            Dim newOriginal = DirectCast(copy.Clone(), T)
            _originals(dbId) = newOriginal
            _originalIndex.Remove(oldOriginal)
            _originalIndex.Add(newOriginal, dbId)
        Next
    End Sub
    Public Sub StartTracking(ByVal dbId As Integer, ByVal item As T)
        Dim newOriginal = DirectCast(item.Clone(), T)
        _originals(dbId) = newOriginal
        _originalIndex(newOriginal) = dbId
        _copies(dbId) = item
        _copyIndex(item) = dbId
    End Sub
    Public Sub StopTracking(ByVal dbId As Integer)
        Dim original = _originals(dbId)
        Dim copy = _copies(dbId)
        _copies.Remove(dbId)
        _originals.Remove(dbId)
        _copyIndex.Remove(copy)
        _originalIndex.Remove(original)
    End Sub
    Public Function IsTracking(ByVal dbId As Integer) As Boolean
        Return _originals.ContainsKey(dbId)
    End Function
    Public Function IsTracking(ByVal item As T) As Boolean
        Return _copyIndex.ContainsKey(item)
    End Function
    Public Function GetItem(ByVal dbId As Integer) As T
        Return _copies(dbId)
    End Function
    Public Function GetId(ByVal item As T) As Integer
        Dim dbId As Integer = (_copyIndex(item))
        Return dbId
    End Function
End Class