一对多关联的数据库在VB.NET中如何新增记录

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有两个表order(orderid,ordername,totalprice), orderdetail(orderid,productid,productname,price) 已经建立一对多

关联(orderid). 用VB.NET建立一个窗体, 用于主表和明细表的数据录入及更新.

在窗体上增加两个sqldataadapter,分别选择order和orderdetail表, 并生成数据集,在DATASET中建立关联(orderid) 主表中:ORDERID,ORDERNAME 绑定在两个TEXTBOX文本框中,用于接受用户的输入,totalprice接受明细表中price

的汇总值.

明细表绑定到一个DATAGRID控件, datasource:dsorderdatamember:order.orderorderdetail建立的关联名称

问题: 在主表中新增一个记录,用户录入orderid和ordername后,进入明细表的录入,用户录入productid, productname, price后,提示 “明细orderID列不允许空值，要更正该值吗？” 是什么原因?

用于连接主表的明细orderID如果输入跟主表一样的orderID时提示“ForeignKeyconstraint 要求在交叉表中存在子键值。要更正该值吗？”

只有录入主表中的orderid和ordername后, 先更新主表数据源,才可以编辑更新明细表,这是为什么? 请问,有没有其他更好的方法, 实现主表和明细表的新增记录同时更新呢? 谢谢关照！网友：方宇 回复：http://qsltz@21cn.comhttp://qsl_tz@hotmail.com

附部分源代码:

Public Class fmOrders

Inherits System.Windows.Forms.Form

Dim WithEvents dtOrderDetails As New DataTable()

Dim BmOrders As BindingManagerBase

Dim BmOrderDetails As BindingManagerBase

Dim OrderDetailsHasChange As Boolean

Dim orderid As DataColumn

dim ordername as datacolumn

Dim SubTotal As DataColumn Private Sub bnFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnFirst.Click

BmOrders.Position = 0

End Sub

Private Sub bnPrior_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnPrior.Click

BmOrders.Position -= 1

End Sub

Private Sub bnNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnNext.Click

BmOrders.Position += 1

End Sub

Private Sub bnLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnLast.Click

BmOrders.Position = BmOrders.Count - 1

End Sub Private Sub bnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnAdd.Click

Try

BmOrders.EndCurrentEdit()

BmOrders.AddNew()

Catch err As System.SystemException

MessageBox.Show(err.ToString)

End Try

End Sub

Private Sub bnLoad_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnLoad.Click

FillData()

End Sub Private Sub bnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnUpdate.Click

Dim dsTestOrdersChange As DataSet BmOrderDetails.EndCurrentEdit()

BmOrders.EndCurrentEdit()

If Not dsTestOrders.HasChanges(DataRowState.Deleted) Then

Try

daOrders.Update(dsTestOrders, "Orders")

daOrderDetails.Update(dsTestOrders, "OrderDetails")

dsTestOrders.AcceptChanges()

Catch err As System.SystemException

dsTestOrders.RejectChanges()

MessageBox.Show(err.ToString)

Throw

End Try

Else

Try

daOrderDetails.Update(dsTestOrders, "OrderDetails")

daOrders.Update(dsTestOrders, "Orders")

dsTestOrders.AcceptChanges()

Catch err As System.SystemException

dsTestOrders.RejectChanges()

MessageBox.Show(err.ToString)

Throw

End Try

End If

End Sub Private Sub fmOrders_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

FillData()

dtOrderDetails = dsTestOrders.Tables("OrderDetails")

BmOrders = Me.BindingContext(dsTestOrders, "Orders")

BmOrderDetails = Me.BindingContext(dsTestOrders, "Orders.OrdersOrderDetails")

OrderDetailsHasChange = True

SubTotal = dsTestOrders.Tables("Orders").Columns("SubTotal")

SubTotal.DefaultValue = 0

Price = dsTestOrders.Tables("OrderDetails").Columns("Price")

Price.DefaultValue = 0

End Sub Private Sub FillData()

dsTestOrders.EnforceConstraints = False

daOrders.Fill(dsTestOrders)

daOrderDetails.Fill(dsTestOrders)

dsTestOrders.EnforceConstraints = True

End Sub

Private Sub dtOrderDetails_ColumnChanged(ByVal sender As Object, ByVal e As System.Data.DataColumnChangeEventArgs) _

Handles dtOrderDetails.ColumnChanged Dim drOrders As DataRow

Dim drOrderDetails As DataRow

Dim iSubTotal As Integer

Try

If OrderDetailsHasChange Then

OrderDetailsHasChange = False

drOrders = dsTestOrders.Tables("Orders").Rows(BmOrders.Position)

iSubTotal = 0

For Each drOrderDetails In drOrders.GetChildRows("OrdersOrderDetails")

iSubTotal = iSubTotal + drOrderDetails("price")

Next

drOrders.BeginEdit()

drOrders("SubTotal") = iSubTotal

drOrders.EndEdit()

End If

Finally

OrderDetailsHasChange = True

End Try

End Sub Private Sub bndelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bndelete.Click

If BmOrders.Count >0 Then

BmOrders.RemoveAt(BmOrders.Position)

End If

End Sub Private Sub bncancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bncancel.Click

BmOrders.CancelCurrentEdit() End Sub

End Class <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"></script>

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如果楼主熟悉VB6，可以直接在项目中添加ADODB的Com引用，这样你就可以像VB6那样 *** 作数据库了！

另外

.NET

Framework中连接数据库要用到ADO.NET。如果要 *** 作Access数据库，要用到System.Data.OleDb命名空间下的许多类。

比如按楼主所说，“我想在textbox1中显示表一中【一些数据】字段下的第一个内容”：

'首先导入命名空间

Imports

System.Data

Imports

System.Data.OleDb

'然后在某一个事件处理程序中写：

Dim

conn

As

New

OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0Data

Source=数据库.accdbJet

OLEDB:Database

Password=MyDbPassword")

Dim

command

As

New

OleDbCommand("Select

*

From

数据表",

conn)

conn.Open()

'打开数据库连接

Dim

reader

As

OleDbDataReader

=

command.ExecuteReader()

'执行SQL语句，返回OleDbDataReader

对象

Do

While

reader.Read()

'读取一条数据

textbox1.Text

+=

reader("一些数据")

&

VbCrLf

Loop

reader.Close()

'关闭OleDbDataReader

conn.Close()

'关闭连接

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

Dim sqlStr As String = "insert into tb values("

Dim i As Integer

For i = 0 To DataGridView1.Columns.Count - 1

sqlStr &= "'" &DataGridView1.Rows(DataGridView1.Rows.Count - 1).Cells(i) &"'"

If i <DataGridView1.Columns.Count - 1 Then sqlStr &= ","

Next

sqlStr &= ")"

Dim con As New SqlConnection(connectionString) '这个自己写去

con.Open()

Dim cmd As New SqlCommand(sqlStr, con)

Try

Dim result As Integer = cmd.ExecuteNonQuery()

If result >0 Then

MsgBox "添加数据成功"

Else

MsgBox "添加数据失败"

End If

Catch (ex As Exception)

MsgBox "添加数据过程发生异常,原因:" &ex.Message

End Try

End Sub

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