VB.Net/Database ADO.net/Table Relation

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DataRelation: Create a relation between the two tables

Imports System
Imports System.Data
Imports System.Windows.Forms
Imports System.Data.SqlClient
public class MainClass
   Shared Sub Main()
       Dim form1 As Form = New Form1
   End Sub
End Class

Public Class Form1
   Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
   Public Sub New()
      "This call is required by the Windows Form Designer.
      "Add any initialization after the InitializeComponent() call
   End Sub
   "Form overrides dispose to clean up the component list.
   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
      If disposing Then
         If Not (components Is Nothing) Then
         End If
      End If
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.IContainer
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
   Friend WithEvents DataSet1 As System.Data.DataSet
   <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
      Me.DataGrid1 = New System.Windows.Forms.DataGrid
      Me.DataSet1 = New System.Data.DataSet
      CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).BeginInit()
      CType(Me.DataSet1, System.ruponentModel.ISupportInitialize).BeginInit()
      Me.DataGrid1.DataMember = ""
      Me.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText
      Me.DataGrid1.Location = New System.Drawing.Point(0, 0)
      Me.DataGrid1.Name = "DataGrid1"
      Me.DataGrid1.Size = New System.Drawing.Size(416, 224)
      Me.DataGrid1.TabIndex = 0
      Me.DataSet1.DataSetName = "NewDataSet"
      Me.DataSet1.Locale = New System.Globalization.CultureInfo("en-GB")
      Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
      Me.ClientSize = New System.Drawing.Size(408, 221)
      Me.Name = "Form1"
      Me.Text = "Form1"
      CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).EndInit()
      CType(Me.DataSet1, System.ruponentModel.ISupportInitialize).EndInit()
   End Sub
#End Region
   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
      "Create Connection object
      Dim thisConnection As New SqlConnection _
         ("server=(local)\SQLEXPRESS;" & _
          "integrated security=sspi;" & _
      " Sql Queries 
      Dim sql1 As String = _
         "SELECT * FROM Employee; "
      Dim sql2 As String = _
         "SELECT * FROM Employee"
      Dim sql As String = sql1 & sql2
      " Create Data Adapter
      Dim da As New SqlDataAdapter(sql, thisConnection)
      " Map Default table names to Employees and Orders
      da.TableMappings.Add("Table", "Employee")
      da.TableMappings.Add("Table1", "Employee")
      " Fill Dataset
      " Create a relation between the two tables
      "Dim dr As New DataRelation( _
      "   "EmployeeOrder", _
      "   DataSet1.Tables(0).Columns("ID"), _
      "   DataSet1.Tables(1).Columns("ID"))
      " Bind the data to the grid at runtime
      DataGrid1.SetDataBinding(DataSet1, "Employee")
   End Sub
End Class

Define Table relation and load combined data into DataGrid

 Imports System
 Imports System.Drawing
 Imports System.Collections
 Imports System.ruponentModel
 Imports System.Windows.Forms
 Imports System.Data
 Imports System.Data.SqlClient
Public Class MainClass
    Shared Sub Main(  )
        Application.Run(New ADOForm1() )
    End Sub
End Class
  Public Class ADOForm1
     Inherits System.Windows.Forms.Form
     Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
     Private components As System.ruponentModel.Container
     " private System.Data.ADO.ADOConnection myConnection;
     Private myConnection As System.Data.SqlClient.SqlConnection
     Private myDataSet As System.Data.DataSet
     Private myCommand As System.Data.SqlClient.SqlCommand
     Private myCommand2 As System.Data.SqlClient.SqlCommand
     Private myDataAdapter As System.Data.SqlClient.SqlDataAdapter
     Private myDataAdapter2 As System.Data.SqlClient.SqlDataAdapter
     Public Sub New(  )
         InitializeComponent(  )
         " create the connection object and open it
         Dim connectionString As String = _
             "server=localhost; uid=sa; " & _
             "pwd=YourPassword; database=northwind"
         myConnection = _
         New System.Data.SqlClient.SqlConnection(connectionString)
         myConnection.Open(  )
         " create the DataSet and set a property
         myDataSet = New System.Data.DataSet(  )
         myDataSet.CaseSensitive = True
         " create the SqlCommand  object and assign the
         " connection and the select statement
         myCommand = New System.Data.SqlClient.SqlCommand(  )
         myCommand.Connection = myConnection
         myCommand.rumandText = "Select * from Employees"
         myCommand2 = New System.Data.SqlClient.SqlCommand(  )
         myCommand2.Connection = myConnection
         myCommand2.rumandText = "Select * from Orders"
         " create the myDataAdapter object and pass in the
         " SQL Command object and establish the table mappings
         myDataAdapter = New System.Data.SqlClient.SqlDataAdapter(  )
         myDataAdapter2 = New System.Data.SqlClient.SqlDataAdapter(  )
         myDataAdapter.SelectCommand = myCommand
         myDataAdapter2.SelectCommand = myCommand2
         myDataAdapter.TableMappings.Add("Table", "Employees")
         myDataAdapter2.TableMappings.Add("Table", "Orders")
         " Tell the myDataAdapter object to fill the DataSet
         Dim myDataRelation As System.Data.DataRelation
         Dim dataColumn1 As System.Data.DataColumn
         Dim dataColumn2 As System.Data.DataColumn
         dataColumn1 = _
         dataColumn2 = _
         myDataRelation = New System.Data.DataRelation( _
             "EmployeesToOrders", dataColumn1, dataColumn2)
         Dim dataSetView As DataViewManager = _
         " display it in the grid
         DataGrid1.DataSource = _
         DataGrid1.DataMember = "Employees"
     End Sub "New
     Private Sub InitializeComponent(  )
         Me.ruponents = New System.ruponentModel.Container(  )
         Me.dataGrid1 = New System.Windows.Forms.DataGrid(  )
         dataGrid1.Location = New System.Drawing.Point(48, 24)
         dataGrid1.Size = New System.Drawing.Size(368, 160)
         dataGrid1.TabIndex = 0
         Me.Text = "ADOFrm1"
         Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
         Me.ClientSize = New System.Drawing.Size(464, 273)
     End Sub 
 End Class

Relational Data Navigation

Imports System.Data.SqlClient
Imports System.Windows.Forms
<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Class Relation
    Inherits System.Windows.Forms.Form
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.cmdClear = New System.Windows.Forms.Button
        Me.cmdFill = New System.Windows.Forms.Button
        Me.lstOrder = New System.Windows.Forms.ListBox
        Me.cmdClear.Anchor = CType((System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.cmdClear.Location = New System.Drawing.Point(210, 238)
        Me.cmdClear.Name = "cmdClear"
        Me.cmdClear.Size = New System.Drawing.Size(72, 24)
        Me.cmdClear.TabIndex = 5
        Me.cmdClear.Text = "Clear"
        Me.cmdFill.Anchor = CType((System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Left), System.Windows.Forms.AnchorStyles)
        Me.cmdFill.Location = New System.Drawing.Point(10, 238)
        Me.cmdFill.Name = "cmdFill"
        Me.cmdFill.Size = New System.Drawing.Size(72, 24)
        Me.cmdFill.TabIndex = 4
        Me.cmdFill.Text = "Fill"
        Me.lstOrder.Anchor = CType((((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
                    Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.lstOrder.IntegralHeight = False
        Me.lstOrder.Location = New System.Drawing.Point(10, 3)
        Me.lstOrder.Name = "lstOrder"
        Me.lstOrder.Size = New System.Drawing.Size(272, 229)
        Me.lstOrder.TabIndex = 3
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(292, 267)
        Me.Font = New System.Drawing.Font("Tahoma", 8.25!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Name = "Relation"
        Me.Text = "Relation"
    End Sub
    Friend WithEvents cmdClear As System.Windows.Forms.Button
    Friend WithEvents cmdFill As System.Windows.Forms.Button
    Friend WithEvents lstOrder As System.Windows.Forms.ListBox
    Private Sub cmdFill_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdFill.Click
        Dim Connect As String = "Data Source=localhost;Integrated Security=True;Initial Catalog=Northwind;"
        Dim con As New SqlConnection(Connect)
        Dim SQL As String = "SELECT * FROM Orders " 
        Dim cmd As New SqlCommand(SQL, con)
        Dim adapter As New SqlDataAdapter(cmd)
        Dim dsNorthwind As New DataSet()
        adapter.Fill(dsNorthwind, "Orders")
        cmd.rumandText = "SELECT * FROM Customers"
        adapter.Fill(dsNorthwind, "Customers")
        cmd.rumandText = "SELECT * FROM Employees"
        adapter.Fill(dsNorthwind, "Employees")
        Dim relCustomersOrders As New DataRelation("CustomersOrders", _
         dsNorthwind.Tables("Customers").Columns("CustomerID"), _
        Dim rowParent, rowChild As DataRow
        For Each rowParent In dsNorthwind.Tables("Customers").Rows
            For Each rowChild In rowParent.GetChildRows(relCustomersOrders)
                lstOrder.Items.Add(rowParent("CompanyName") & _
                 " ordered on " & rowChild("OrderDate"))
    End Sub
    Private Sub cmdClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdClear.Click
    End Sub
End Class