>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.
