我自己写机房的时候，看非常多高人的博客，各种的借鉴，当初务必的纠结，如今整个机房敲完了，写这篇博客给大家一个总体上的、简单理解的七层，期望大家看完这篇文章之后，不会这个纠结了。

  首先大家得看了我的上一篇博客：

  http://blog.csdn.net/qiumuxia0921/article/details/33738319

  我再说就会好说一点，大家仅仅要理解了那张包图之后就能够了。

  首先我还是拿最老套、最简单、最先開始的样例Login開始：

  1、我们要知道Login须要那几步：查询user表，推断用户是否存在；在worklog中加入用户日志。

  2、须要的数据库设计：

  这里我就不另外建表，这样大家看的更熟悉，是吧？

  3、建立Entity

  实体是依据表来建立的，也就是说，表中有几个字段，Entity的LoginEntity和WorklogEntity类就有几个property。

  本着面面俱到的原则，我就晒晒代码，大家别嫌我麻烦：

'**************************
'文 件 名：UserLogin
'命名空间：Entity
'内    容：
'功    能：
'文件关系：
'作    者：邱慕夏
'小    组：邱慕夏
'生成日期：2014-06-07 17:27:28
'版 本 号：V1.0.0.0
'改动日志：
'版权说明：
'***************************
Public Class LoginEntity
#Region "定义变量"
    Private _userID As String
    Private _level As String
    Private _Head As String
    Private _password As String
    Private _oldpassword As String
    Private _userName As String
    Private _computer As String

#End Region
    Public Shared UserHead As String              '设置全局变量
    Public Shared UserLevel As String
    Public Property UserID() As String            '将T_User_DAL表中的每个实体都传上去，实体是依据表来建的，不是功能
        Get
            Return _userID
        End Get
        Set(ByVal value As String)
            _userID = value
        End Set
    End Property
    Public Property Level() As String
        Get
            Return _level
        End Get
        Set(ByVal value As String)
            _level = value
        End Set
    End Property
    Public Property Head() As String
        Get
            Return _Head
        End Get
        Set(ByVal value As String)
            _Head = value
        End Set
    End Property
    Public Property Password() As String
        Get
            Return _password
        End Get
        Set(ByVal value As String)
            _password = value
        End Set
    End Property
    Public Property OldPassword() As String
        Get
            Return _oldpassword
        End Get
        Set(ByVal value As String)
            _oldpassword = value
        End Set
    End Property
    Public Property UserName() As String
        Get
            Return _userName
        End Get
        Set(ByVal value As String)
            _userName = value
        End Set
    End Property
    Public Property computer() As String
        Get
            Return _computer
        End Get
        Set(ByVal value As String)
            _computer = value
        End Set
    End Property

End Class

  上面是LoginEntity的，以下是Worklog的：

'**************************
'文 件 名：WorkLogEntity
'命名空间：Entity
'内    容：
'功    能：
'文件关系：
'作    者：邱慕夏
'小    组：邱慕夏
'生成日期：2014/6/15 11:07:47
'版 本 号：V1.0.0.0
'改动日志：
'版权说明：
'***************************
Public Class WorkLogEntity
    Private _userid As String
    Private _level As String
    Private _loginDateTime As String
    Private _LogoutDateTime As String
    Private _computer As String
    Private _status As String
    Public Shared Property Login_DateTime As String


    Public Property UserID() As String
        Get
            Return _userid
        End Get
        Set(ByVal value As String)
            _userid = value
        End Set
    End Property
    Public Property Level() As String
        Get
            Return _level
        End Get
        Set(ByVal value As String)
            _level = value
        End Set
    End Property
    Public Property LoginDateTime() As String
        Get
            Return _loginDateTime
        End Get
        Set(ByVal value As String)
            _loginDateTime = value
        End Set
    End Property
    Public Property LogoutDateTime() As String
        Get
            Return _LogoutDateTime
        End Get
        Set(ByVal value As String)
            _LogoutDateTime = value
        End Set
    End Property
    Public Property Computer() As String
        Get
            Return _computer
        End Get
        Set(ByVal value As String)
            _computer = value
        End Set
    End Property
    Public Property Status() As String
        Get
            Return _status
        End Get
        Set(ByVal value As String)
            _status = value
        End Set
    End Property
End Class

  以上都是准备工作，因为篇幅，看下一篇。