From a database structure point of view, it is best to have another table with the dimensions, weights, ...

However that doesn't solve your problem if you want to combine different products into one package.

What you are asking is solving a three dimensional puzzle. If you want to do it exactly it will be quite difficult, although there is probably some mathematical algorithm that will just do so.

A few quick checks however will allow you to approximate the box:

• The box must have a volume larger that the total volume of the products (including packing)
• the largest length of each product must be less than the largest "length" of the box.

Such a quick check will probably already eliminate a number of boxes. Then add a suitable "safety margin" and take the smallest box that still remains. That will probably be OK for 90% or so of all cases.