一对多关联的数据库在VB.NET中如何新增记录

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:dsorder; datamember: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.com

http://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