public static void CreateRelationship()
{
DataSet dataSet = new DataSet();
DataTable orderTable = new DataTable();
DataTable itemTable = new DataTable();
//ExStart
//ExId:NestedMailMergeCreateRelationship
//ExSummary:Shows how to create a simple DataRelation for use in nested mail merge.
dataSet.Relations.Add(new DataRelation("OrderToItem", orderTable.Columns["Order_Id"], itemTable.Columns["Order_Id"]));
//ExEnd
}