VB.net adding code to find the joins between SQL tables

Hi. I am using the following code to get the names of a SQL database. What code would I add to find relationships between any of the tables. Thanks


 Public Sub Populate_TreeView_From_SQL()

        Dim SQLExpression As String = _
            "SELECT TABLE_NAME, COLUMN_NAME FROM information_schema.columns ORDER BY TABLE_NAME,COLUMN_NAME"

        Dim Rootnode As TreeNode = Nothing
        Dim Mainnode As TreeNode = Nothing
        Dim Childnode As TreeNode = Nothing

        Dim MainName As String = String.Empty

        Dim oConnectionString As String = Me.RichTextBox1.Text
        Dim cn As New SqlConnection(oConnectionString)

        Dim adp As New SqlDataAdapter(SQLExpression, cn)

        Dim ds As New DataSet

        adp.Fill(ds, "SystemData")

        Me.TreeView_From.Nodes.Clear()
        'Dim Con As String = "server=196.220.43.247,1444;uid=murbro73;pwd=chestnut3;database=test"
        Rootnode = Me.TreeView_From.Nodes.Add(key:="Root", text:="database name here", _
                                        imageIndex:=0, selectedImageIndex:=0)



        For Each row As DataRow In ds.Tables("SystemData").Rows

            If MainName <> row(0).ToString Then
                Mainnode = Rootnode.Nodes.Add(key:="Table", text:=row(0).ToString, _
                imageIndex:=1, selectedImageIndex:=1)
                MainName = row(0).ToString
            End If

            Childnode = Mainnode.Nodes.Add(key:="Column", text:=row(1).ToString, _
            imageIndex:=2, selectedImageIndex:=2)

        Next

        Me.TreeView_From.Nodes(0).EnsureVisible()
        Me.TreeView_From.ExpandAll()
        Me.TreeView_From.Scrollable = True

        ds.Dispose()
        ds = Nothing
        adp.Dispose()
        adp = Nothing
        cn.Dispose()
        cn = Nothing

    End Sub