具有属性（变量）产品的数据库设计？

Question

Hello I have two tables with many to many relationship and a junction table. In short, products with different attributes which have added price with them. to make it more clear I It's product and attribute table.

+-------------+-----------+-------------------+ | product | attribute | attribute_product | +-------------+-----------+-------------------+ | id | id | product_id | | name | name | attribute_id | | description | | attribute_value | | price | | added_price | +-------------+-----------+-------------------+

as Laravel doesn't support multi column primary key I want the attribute_product table to have a primary key and when I call $product->attribute->attach() it automatically increment it, so I can do the following :

+---------+----------------------+ | cart | cart_product | +---------+----------------------+ | id | cart_id | | user_id | attribute_product_id | +---------+----------------------+

In my head I'm gonna make a model for attribute_product table and call it Item and therefore a cart can have multiple Items, and I can show it like $cart->items->groupBy('product_id') so I can have it all there in the user's cart.

Any solution or a better suggestion is very much appreciated.

Answer 1

Well, I think that maybe you aren't focusing it in the right way. If you have a belongsToMany relationship between product and attribute , is because a product may have multiple attributes without being a different product .

In your cart you should add a product, not an specific attribute of a product. For example:

I want a water bottle, but only the water, without the bottle.

This makes no sense, you can not buy a water bottle without the bottle. In that case you will be buying water, not a water bottle, which should be different products, not the same one.

The cart_product table should look like this, as long as there is no compelling reason why it can not be so.

 +---------+----------------------+
 |  cart   |     cart_product     |
 +---------+----------------------+
 | id      | cart_id              |
 | user_id | product_id           |
 +---------+----------------------+