毕业设计超市系统（四）数据访问层

接着上一篇，由于用到的是linq来做数据处理，所以我为数据访问层建立一个名为DBBase的类它有一个Marketdc的属性为子类所有代码如下：

 

Imports SiYaoMin.ProForLeave.MyLINQ
Public Class DBBase
    Protected _marketdc As MarketDataContext
    Public Sub New()
        _marketdc = New MarketDataContext(ConnectionInfo.ConnectionString)
    End Sub
    Protected Property Marketdc() As MarketDataContext
        Get
            Return _marketdc
        End Get
        Set(ByVal value As MarketDataContext)
            _marketdc = value
        End Set
    End Property
    Public Sub UpdataSource()
        _marketdc.SubmitChanges()
    End Sub
End Class

 

DBBase类中涉及到一个ConnectionInfo类，它的代码如下：

 

Public Class ConnectionInfo
    Private Shared _DataSource As String
    Public Shared Property DataSource() As String
        Get
            Return _DataSource
        End Get
        Set(ByVal value As String)
            If value.Trim = String.Empty Then
                _DataSource = "."
            End If
            _DataSource = value
        End Set
    End Property
    Private Shared _DataBaseName As String
    Public Shared Property DataBaseName() As String
        Get
            Return _DataBaseName
        End Get
        Set(ByVal value As String)
            _DataBaseName = value
        End Set
    End Property
    Private Shared _Trusted_Connection As Boolean
    Public Shared Property Trusted_Connection() As Boolean
        Get
            Return _Trusted_Connection
        End Get
        Set(ByVal value As Boolean)
            _Trusted_Connection = value
        End Set
    End Property
    Private Shared _UserID As String
    Public Shared Property UserID() As String
        Get
            Return _UserID
        End Get
        Set(ByVal value As String)
            _UserID = value
        End Set
    End Property
    Private Shared _Password As String
    Public Shared Property Password() As String
        Get
            Return _Password
        End Get
        Set(ByVal value As String)
            _Password = value
        End Set
    End Property
    Public Shared ReadOnly Property ConnectionString() As String
        Get
            If _Trusted_Connection Then
                Return "Data Source=" + _DataSource + ";Initial Catalog=" + _DataBaseName + ";trusted_connection=true"
            Else
                Return "Data Source=" + _DataSource + ";Initial Catalog=" + _DataBaseName + ";Persist Security Info=True;User ID=" + _UserID + ";Password=" + _Password
            End If
        End Get
    End Property
    
End Class

 

主要是生成数据库连接字符串，这里只写了ms sql server的数据库连接字符串。

我采用每一个类只有一种单独的功能的方法。

 

贴个图：

由于数据访问涉及到了增、删、改、查。下面各有一个例子：

 

Imports SiYaoMin.ProForLeave.MyLINQ

Public Class AddGoodsData
    Inherits DBBase
    Private _goods As GoodsDetail
    Public Property Goods() As GoodsDetail
        Get
            Return _goods
        End Get
        Set(ByVal value As GoodsDetail)
            _goods = value
        End Set
    End Property

    Public Function Add() As Integer
        Dim a As Integer = _marketdc.AddGoodsDetail(_goods.goodsid, _goods.goodsname, _goods.types, _goods.price, _goods.shelflife, _goods.madein, _goods.company, _goods.info)
        Return a
    End Function
End Class

 

 

Imports SiYaoMin.ProForLeave.MyLINQ
Public Class DeleteLoginInName
    Inherits DBBase
    Private _logininfo As Login
    Public Property LoginInfo() As Login
        Get
            Return _logininfo
        End Get
        Set(ByVal value As Login)
            _logininfo = value
        End Set
    End Property

    Public Function Delete() As Integer
        Dim a As Integer = _marketdc.DeleteLoginInfo(_logininfo.loginname)
        Return a
    End Function
End Class

 

 

Imports SiYaoMin.ProForLeave.MyLINQ
Public Class UpdateGoodsData
    Inherits DBBase
    Private _goods As GoodsDetail
    Public Property Goods() As GoodsDetail
        Get
            Return _goods
        End Get
        Set(ByVal value As GoodsDetail)
            _goods = value
        End Set
    End Property

    Public Function Update() As Integer
        Dim a = _marketdc.UpdateGoodsDetail(_goods.goodsid, _goods.goodsname, _goods.types, _goods.price, _goods.shelflife, _goods.madein, _goods.company, _goods.info)
        Return a
    End Function
End Class

 

 

Imports SiYaoMin.ProForLeave.MyLINQ
Public Class GetGoodsInfo
    Inherits DBBase

    Public Function GetAllGoods() As IList
        Return _marketdc.GetAllGoodsInfo().ToList()
    End Function

    Public Function GetFilterGoods() As IList
        Return _marketdc.FilterGoodsInfo(_goods.goodsname, _goods.company, _goods.types).ToList
    End Function
    Public Function GetGoodsCompanyList() As IList
        Return _marketdc.GetGoodsComany().ToList
    End Function
    Public Function GetGoodsNameList() As IList
        Return _marketdc.GetGoodsNames().ToList
    End Function
    Public Function GetGoodsTypesList() As IList
        Return _marketdc.GetGoodsTypes().ToList
    End Function
    Public Function GetGoodsNamesListInType() As IList
        Return _marketdc.GetGoodsNamesInTypes(_goods.types).ToList
    End Function
    Public Function GetGoodsTypeForSale() As IList
        Return _marketdc.GetGoodsTypesForSale().ToList
    End Function
    Public Function GetGoodsPriceForSaleInName()
        Return _marketdc.GetGoodsPriceListInName(_goods.goodsname).ToList
    End Function
    Public Function GetGoodsPriceForSaleInGoodsId()
        Return _marketdc.GetGoodsPriceListInGoodsId(_goods.goodsid).ToList
    End Function
    Private _goods As GoodsDetail
    Public Property Goods() As GoodsDetail
        Get
            Return _goods
        End Get
        Set(ByVal value As GoodsDetail)
            _goods = value
        End Set
    End Property
End Class