Although I\'m guilty of this crime, it seems to me there can\'t be any good reason for a table to not have an identity field primary key.
Pros: - whether you want to o
Every table should have a primary key. But it doesn't need to be a single field identifier. Take for example in a finance system, you may have the primary key on a journal table being the Journal ID and Line No. This will produce a unique combination for each row (and the Journal ID will be a primary key in its own table)
Your primary key needs to be defined on how you are going to link the table to other tables.