Can I use VARCHAR as the PRIMARY KEY?

Question

I have a table for storing coupons/discounts, and I want to use the coupon_code column as the primary key, which is a VARCHAR.

My rationale is that, eac

Answer 1

It depends on the specific use case.

If your table is static and only has a short list of values (and there is just a small chance that this would change during a lifetime of DB), I would recommend this construction:

CREATE TABLE Foo 
(
    FooCode VARCHAR(16), -- short code or shortcut, but with some meaning.
    Name NVARCHAR(128), -- full name of entity, can be used as fallback in case when your localization for some language doesn't exist
    LocalizationCode AS ('Foo.' + FooCode) -- This could be a code for your localization table... 
)

Of course, when your table is not static at all, using INT as primary key is the best solution.