2010/5/4 Grzegorz Jaśkiewicz <gryz...@gmail.com>: > > Another thing, If your PK changes, it is no longer a PK, you can't rely on it.
Depending upon what you mean by changes this could be true or it could be a matter of opinion. If your referring to a candidate key's value changes, this key still provides a useful way to identify a tuple. Also, just because a surrogate key is a useful way to identify a row, by itself it does nothing to uniquely identify an entity that a row represents. On some DBMS forums that I frequent, it is a daily occurrence to see questions on how to eliminate duplicate rows. So, for some people, there are times when even surrogate keys cannot be relied upon as a PK. -- Regards, Richard Broersma Jr. Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
