OK so which is the "correct" way to do it? E.g., Say I have a table with users, and a table with clubs, and a table that links them. Each user can be in more than one club and each club has more than one member. Standard M:M relationship. Which link table is the "right" way to do it? This: CREATE TABLE ( userid INTEGER NOT NULL REFERENCES users, clubid INTEGER NOT NULL REFERENCES clubs, PRIMARY KEY (userid, clubid) ); Or this: CREATE TABLE ( id SERIAL PRIMARY KEY, userid INTEGER NOT NULL REFERENCES users, clubid INTEGER NOT NULL REFERENCES clubs ); I've always favored natural keys (the first option) as it just seems to me a more natural and semantic representation of the data, however I often get app designers complaining about it being more complex or something. Comments?