Public Class db
    Private _cn As OleDb.OleDbConnection
    Private _da As OleDb.OleDbDataAdapter
    Private _sql As OleDb.OleDbCommand
    Public Function connect() As OleDb.OleDbConnection
        _cn = New OleDb.OleDbConnection("DEIN_CONNECTION_STRING")
        _cn.Open()
        Return _cn
    End Function
    Public Function updateTable(ByRef dt As DataTable) As Boolean
        Dim dt_tmp As DataTable
        Try
            If Not dt.HasErrors Then
                dt_tmp = dt.GetChanges
                Me._da.Update(dt_tmp)
            Else
                Return False
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
            Return False
        End Try
        Return True
    End Function
    Public Function fillTable(ByVal sql As String, ByRef dt As DataTable) As _
      Boolean
        Try
            _sql = New OleDb.OleDbCommand(sql, Me.connect)
            _da = New OleDb.OleDbDataAdapter(_sql)
            _da.Fill(dt)
        Catch ex As Exception
            MsgBox(ex.Message)
            Return False
        End Try
        Return True
    End Function
End Class

 Dim db As New db ' KLASSE DB INSTANZIEREN
 Dim dt As New DataTable ' DATATABLE ERSTELLEN
 If db.fillTable("SELECT * FROM WAS_AUCH_IMMER", dt) Then
   ' ERFOLGREICH GEFÜLLT
 End If
 If db.updateTable(dt) Then
   ' ERFOLGREICH AKTUALISIERT 
 End If