Sub update(ByVal data As DateTime, ByVal Cassa As Double, ByVal userid As String)
        Dim stringasql As String
        stringasql = "UPDATE Account SET cassa=" & Cassa.ToString & " WHERE data='" & data.ToShortDateString & "' AND user_id=" & userid.ToString
        Dim risputente As Integer

        Try
            objcomm = New OleDbCommand(stringasql.ToString, objconn)
            risputente = objcomm.ExecuteNonQuery()

        Catch es As Exception
            MsgBox(es)
        End Try
    End Sub