Should I design a table with a primary key of varchar or int?

Question

I know this is subjective, but I\'d like to know peoples opinions and hopefully some best practices that I can apply when designing sql server table structures.

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Answer 1

I'd agree that in general an INT (or identity) field type is the best choice in most "normal" database designs:

• it requires no "algorithm" to generate the id/key/value
• you have fast(er) joins and the optimizer can work a lot harder over ranges and such under the hood
• you're following a defacto standard

That said, you also need to know your data. If you're going to blow through a signed 32-bit int, you need to think about unsigned. If you're going to blow through that, maybe 64-bit ints are what you want. Or maybe you need a UUID/hash to make syncing between database instances/shards easier.

Unfortunately, it depends and YMMV but I'd definitely use an int/identity unless you have a good reason not to.