database - Surrogate vs. natural/business keys -

here go again, old argument still arises...

would better have business key primary key, or rather have surrogate id (i.e. sql server identity) unique constraint on business key field?

please, provide examples or proof support theory.

both. have cake , eat it.

remember there nothing special primary key, except labelled such. nothing more not null unique constraint, , table can have more one.

if use surrogate key, still want business key ensure uniqueness according business rules.