OOP模式设计(数据访问)的常用方法是什么？

最初有一个DAL对象,我的BO呼叫信息,然后传递给UI.然后我开始注意到UI中的代码减少,并且有Controller类.什么是体面的推荐.

我目前正在构建我的

Public Class OrderDAL

    Private _id Integer
    Private _order as Order

    Public Function GetOrder(id as Integer) as Order

        ...return Order

    End Function

End Class

然后我有控制器类(最近实现了这种风格)

Public Class OrderController

    Private Shared _orderDAL as new OrderDAL

    Public Shared Function GetOrder(id) As Order

        Return _orderDAL.GetOrder(id)

    End Function

End Class

然后在我的申请中

My app Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        msgbox(OrderController.GetOrder(12345).Customer.Name)

    End Sub


End app

我最初发现使用共享类时,无论何时需要获取数据,我都不必继续创建DAL的新实例

Dim _orderDAL as New OrderDal

_orderDAL.GetOrder(1234)

.....

你有什么看法？

谢谢