private void DetachPurchaseOrderDetails(PurchaseOrderDetail entity)
 {
     entity.PurchaseOrder = null;
 }
 private bool FilterPurchaseOrderDetails(PurchaseOrderDetail entity)
 {
     return (entity.PurchaseOrderID == this.PurchaseOrderID);
 }
 private void AttachPurchaseOrderDetails(PurchaseOrderDetail entity)
 {
     entity.PurchaseOrder = this;
 }