Should I use a string that's varchar (30) (unique) as a primary key?

[bugboy]

I have a table of words which are all unique and will not change.. can i use the words themselves as the primary key or is it better to use an integer?

I think it would simplify my queries a great deal if I didn't have to retrieve the primary key for the word /or the word for the key every time i query. I'm looking for the best efficiency but maybe i'm splitting hairs here?

I've read that strings make lousy keys. But since mine are all unique and never change, i'm just wonder what the common practice would be?

Thanks!

BugBoy

[forse]

Hi,

For example, if you are using email addresses, they will surely be unique. But it is better to use a separate field as your primary key (eg. bigint auto_increment values). Just because it is unique, doesn't mean you should use it as primary key.

[bugboy]

Thanks forse!

Is it better because it's faster to query or because it's more stable (less likely to change over time)?