Check out the
COM_ShoppingCartSKU table. Add some items to the cart and query that table to see the results. You'll find the
SKUID and the
CartItemParentGUID will be a combination of how things work out. This is very specific if you're using options for products. If you're just using "flat" products without options, then the
SKUID will be unique.
When I say flat products I mean something like a hat that is one size fits all, with no color options. Or a set of headphones that are black with no color options.
If you were to have more complex products, it could be hat with youth and adult sizing options as well as 3 different colors. Or a set of headphones with black, silver and red color options as well as Bluetooth or no Bluetooth options.