Two records in the same table must be related somehow
I believe the requirement to record &quot;these 2+ items are used to make this 1 bigger item&quot; is called a BOM. (Bill Of Materials).
The only set of BOM tables I've seen in action used 1 table for each depth.  Your BOM would only need the two tables.
TL;DR - use the &quot;association table&quot;.