On Mon, Apr 13, 2009 at 5:18 PM, Richard Broersma <richard.broer...@gmail.com> wrote: >> Your PK is a composite of (entry, order)? Won't your foreign keys >> elsewhere all break when you shift the order around? > > If there really are foreign keys, then an update will not be allowed > to shift a primary key unless the foreign key is set with ON UPDATE > CASCADE then the shifts will be cascaded to all references > automatically.
Right. I'm still dusting off my SQL after a long period of corrosion. :) The same applies, though, if you have external references to the PK; for example, if you have a web interface where "/sense/10/3" refers to entry 10, sense 3. If your senses are reordered by someone else, and you operate on /10/3, you may suddenly find yourself viewing or modifying (or deleting!) a different sense. This could even happen within the same transaction, if you're not very careful with locking... -- Glenn Maynard -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
