its not possible to crat a tabel

Hallo guys,

i use HeidiSql and i find this tool very nice.

So im learning for programming of shops, and i hope you can help me.

I try to program in Heidi my tabel, so that it is not possible to put the same product into the shopping cart twice.

whi i get this error message?

I suppose you need to uncheck "unsigned" on the product_id column in the cart table. The parent column product.id is defined as signed.