I think a database with all natural keys is unrealistic. For example if you have a table that refers to people, are you going to use their name as a primary key? Names change all the time due to things like marriage, divorce, or trouble with the law. We have tables with 20 million rows which reference back to a table of people, and if I used the person's name as key, it would be a major pain when somebody's name changes. Even if there is referential integrity, one person might be referred to by 25% of the 20 million rows, so the update would take quite a long time. Also the table will be filled with dead rows and the indexes will likely be bloated. If I want to clean that up, it will take a vacuum full or a cluster which will lock the whole table and run for hours. If I use a surrogate key, I can change their name in one row and be done with it. Just my 2 cents. Dave
