well this is the situation, right now we are in a transition number process (we are changing from old to new part numbers) and my supervisor wants to keep the old number as a reference in the main table. Also he wants to do an extra table named alias that will contain only new and old numbers (no extra info) example ; the fields will be part number (new No.) alias (old No.) partalias (newold), and aliaspart (oldnew) but I also will have build a table with Model Numbers this table will be related to Parts Table so we can see which parts are needed to build each model. how do I relate these 3 tables since in the Model table we just want the new numbers to appear.