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
A primary key is ALWAYS a good idea. It allows for very fast and easy joining of tables. It aides external tools that can read system tables to make join allowing less skilled people to create their own queries by drag-and-drop. It also makes the implementation of referential integrity a breeze and that is a good idea from the get go.