In many cases a customer is looking to merge sales of old item data into a newer existing item so that they can get a more complete historical record of sales, even an item's sku number may change in the retailers reporting system. Lots of times, a new sku is generated simply due to a minor packaging change or some other factor not critical to the item's performance. This When this happens, the history can become muddled, but we don't want to simply change the item number historically as this will make an foresnics never match the historical base data. Instead, we can get around this by creating a categorization of items that for most items is just its item number. In the case of the old item number that we want consolidated, we'll use the new items' value for this category - that way when we report on the category and aggregate by it, the sales of old and new will be combined into one nice total. This document provides some strategies on how to manage these changes to get a flexible picture without altering history in the database itself.
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