What is the most efficient method to use datarelations to obtain the childrows going down more than one level. For example assuming I have the ubiquitous Customer/Order/Product schema and assuming that I have established the datarelations between Customer-Order and Order-Product. How would i obtain all of the Product records for a given customer?
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What I really need to do is get the records into a dataset of some kind that I can work with like an array of datarows or a datatable/dataview or something. I guess I could create an array of datarows the size of "product" and then use the inner loop to add each of the product rows to that array. In my schema I don't need to worry about creating duplicate rows in the array. Any other ideas?
Well
I made something similar to what you are asking, if you modify this to your own data then here is routine that collect's a child's table data into a array
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim i As Integer = 0
Dim tmptbl As New DataTable
Dim dr As DataRow
Dim dv As New DataView(tmptbl)
tmptbl.Columns.Add("Compan
tmptbl.Columns.Add("Total_
'tmptbl.Columns.Add("Total
' Dim an array of datarows to hold the child records.
Dim drarray() As DataRow
'Look up all rows in the company table
For Each companyRow In ds.Tables("Company").Rows
'Select the first(row) the company table and get its belonging child data
drarray = ds.Tables("Company").Rows(
' Check weather a company has childrows ( if it has any orders)
'For Each orderRow In companyRow.GetChildRows("r
If drarray.Length() <> 0 Then
dr = tmptbl.NewRow()
dr(0) = drarray(0).Item(0).ToStrin
dr(1) = drarray.Length()
tmptbl.Rows.Add(dr)
End If
i += 1
Next
grdOrders.DataSource = dv
End Sub
Hope this helps
vbturbo
I ended up using a variation of your last suggestion. I have posted the code below for the sake of completeness. I still have some testing to validate the logic but I think it'll work. I may have to copy the datarows instead of just adding them to the new table.
thank you for your help
Private Function GetFieldElements(ByVal rowField As DataRow) As DataTable
Dim dtFieldProcElem As DataTable = _dsFD.Tables("ProcessedEle
Dim rowElements As DataRow()
Dim rowElement As DataRow
Dim rowProcElems As DataRow()
Dim rowProcElem As DataRow
rowElements = rowField.GetChildRows("FK_
For Each rowElement In rowElements
rowProcElems = rowElement.GetChildRows("F
For Each rowProcElem In rowProcElems
dtFieldProcElem.Rows.Add(r
Next
Next
Return dtFieldProcElem
End Function
Business Accounts
Answer for Membership
by: vbturboPosted on 2007-01-25 at 12:29:43ID: 18399052
Hi BriCrowe
I think this is what you are looking for
Dim customerOrdersRelation As DataRelation = _
customerOrders.Relations.A
customerOrders.Tables("Cus
customerOrders.Tables("Ord
Dim orderDetailRelation As DataRelation = _
customerOrders.Relations.A
customerOrders.Tables("Ord
customerOrders.Tables("Ord
Dim orderProductRelation As DataRelation = _
customerOrders.Relations.A
customerOrders.Tables("Pro
customerOrders.Tables("Ord
Dim custRow, orderRow, detailRow As DataRow
For Each custRow In customerOrders.Tables("Cus
Console.WriteLine("Custome
For Each orderRow In custRow.GetChildRows(custo
Console.WriteLine(" Order ID: " & orderRow("OrderID").ToStri
Console.WriteLine(vbTab & "Order Date: " & _
orderRow("OrderDate").ToSt
For Each detailRow In orderRow.GetChildRows(orde
Console.WriteLine(vbTab & " Product: " & _
detailRow.GetParentRow(ord
("ProductName").ToString()
Console.WriteLine(vbTab & " Quantity: " & _
detailRow("Quantity").ToSt
Next
Next
Next
http://msdn2.microsoft.com
vbturbo