SQL field with multiple id's of other table

Question

Could someone give me an idea how to create this database structure. Here is an example:

Table \"countries\":
id, countryname
1, \"US\"
2, \"DE\"
3, \"FR\"
4         


        

Answer 1

the best approach for relational databases is the following :

One table for coutries, let's say country_id, country_desc (country_id is primary)

one table for products, let's say product_id, product_desc and as many columns as you want (product_id is primary)

if you had only one country for sure, it'd be enough to have a foreign key pointing to country_id in each product row. Having a foreign key asserts that there is an actual country behing a country_id referring to country table.

In your case you have several countries for a product, so add a separate association table product_id, country_id

both keys primary and both foreign as well.