What's the best practice for primary keys in tables?

Question

When designing tables, I\'ve developed a habit of having one column that is unique and that I make the primary key. This is achieved in three ways depending on requirements

Answer 1

Besides all those good answers, I just want to share a good article I just read, The great primary-key debate.

Just to quote a few points:

The developer must apply a few rules when choosing a primary key for each table:

• The primary key must uniquely identify each record.
• A record’s primary-key value can’t be null.
• The primary key-value must exist when the record is created.
• The primary key must remain stable—you can’t change the primary-key field(s).
• The primary key must be compact and contain the fewest possible attributes.
• The primary-key value can’t be changed.

Natural keys (tend to) break the rules. Surrogate keys comply with the rules. (You better read through that article, it is worth your time!)