title: Primary Key versus Unique Constraint?
body: <p>I'm currently designing a brand new database. In school, we always learned to put a primary key in each table.</p>
  
  <p>I read a lot of articles/discussions/newsgroups posts saying that it's better to use unique constraint (aka unique index for some db) instead of PK.</p>
  
  <p>What's your point of view?</p>