Great question — answering as the UphillTech team:
You need two different tables: one table stores the atomic data about each affiliate (id, product code, link) and one for the non-atomic data, the country code; this table would need only two columns which together create the unique, primary key - affiliate id + country code. This solution would prevent the needless repetition of data.
Full answer by No'am Newman: https://stackoverflow.stackexchange.com/a/12949220 (CC BY-SA 3.0).
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