>Adding a surrogate key to such a table just adds overhead, although that could be useful >in case specific rows need updating or deleting without also modifying the other rows with >that same data - normally, only insertions and selections happen on such tables though, >and updates or deletes are absolutely forbidden - corrections happen by inserting rows with >an opposite transaction. I routinely add surrogate keys like serial col to a table already having a nice candidate keys to make it easy to join tables. SQL starts looking ungainly when you have a 3 col primary key and need to join it with child tables.
