Absolutely. An order is a snapshot of the moment in time the order was created. It may be necessary to allow price revisions on an order by order basis, according to business rules, but you sure don't want the value of past orders changed -- made wrong -- when the current price changes.

>Is the price in the Inventory table related to the current selling price? IOW, if the price of an item change, do you change the Inventory price field? If so, my guess would be that you need to add a price field in the OrderDetails table to keep the original price (at the time of the purchase). You don't want an invoice that change with the fluctuations of the items prices.
>
>>Ok, this would be a most complicated question for the day (or beginning of the day).
>>
>>Here is a method I'm duplicating:

>/// <summary>
>>        /// Get Order Subtotal
>>        ///     returns the subtotal of all items in a given order.
>>        /// </summary>
>>        /// <param name="dt"></param>
>>        /// <returns></returns>
>>        public decimal GetOrderSubTotal(OrderDetailsDS.OrderDetailsDataTable dt)
>>        {
>>            decimal subtotal = 0.00M;
>>            foreach (OrderDetailsDS.OrderDetailsRow  dr in dt.Rows)
>>            {
>>                if (!dr.RowState.Equals(DataRowState.Deleted) || !dr.RowState.Equals(DataRowState.Detached))
>>                {
>>                    subtotal += (dr.Qty  * (decimal)dr.); // not yet complete
>>                }
>>            }
>>
>>            return subtotal;
>>        }

>However, in my case the Price is in the Inventory table and I don't have it in OrderDetails. So, what should be my approach to take here?
>>
>>1. Add the Price field to the table OrderDetails?
>>
>>2. Somehow add this field from the Inventory related table into TA?
>>
>>3. On each record attempt to retrieve Price from another table?