Unify specific tables in one product table Today my database has the tables in this first image. The problem is that now I need to do stock control and other products will be added too.



To support many types of products, first I designed the tables in the next image (design 1). This will be a solution to generic products that don't have any kind of serial number to differentiate they.

After doing some research I found the solution in the next image (design 2). This supports generic and the specific products (like SIM cards and devices). I think that the complexity will increase greatly this way. Also there is a problem that I have FKs in simcards and devices. One great thing about this solution is that will support future products with specific data.



What is the best approach to solve this problem?
Why not add product_type_attributes into design 1? If product_type_attributes is necessary and it is in multiple types then design 2 is much better compared to design 1 because it is more normalized.