public QueryOrderDef AddOrderDef(Guid id, bool asc)
        {
            var attr     = AddAttribute(id);
            var orderDef = new QueryOrderDef {
                Attribute = attr, Asc = asc
            };

            Def.OrderAttributes.Add(orderDef);
            return(orderDef);
        }
        public QueryOrderDef AddOrderDef(string name, bool asc)
        {
            var attr     = AddAttribute(name);
            var orderDef = new QueryOrderDef {
                Attribute = attr, Asc = asc
            };

            Def.OrderAttributes.Add(orderDef);
            return(orderDef);
        }