g == gryzman@xxxxxxxxx writes: g> you should use it, whenever you need db to keep its own key internally. g> Advantage of sequence is also the fact, that you can have the sequence g> value used on different columns/tables . g> My rule of thumb is , in that case: as long as it is a short type (not g> of toastable, or/and variable length), and as long as it won't change, g> and is unique - I can use it. Otherwise, I use sequence to connect g> rows internally for database. g> First rule, is because of index access, and the way btree works. g> Second is, because update of value will update other rows too - and g> HOT won't help you here, so that's not efficient. And also, forcing it g> to be unique is harder than. g> Hth. That does help. So, in my example of a table consisting of rows for each periodic table element, the atomic number would suffice as a unique key since, well, it's unique and not going to change. Right? -- Brandon -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
