Matthew Wilson <matt@xxxxxxxxxx> wrote: > I have a table like this: > > create table event( > > destination_id integer not null references destination > (destination_id), > > starts timestamp, > ends timestamp > ); > > I want to make sure that no two rows **with the same destination_id** > overlap in time. > > I'm not sure how to write this exclusion constraint. I know how to make > the constraint to prevent any two rows from overlapping, but I want to > allow rows to overlap as long as they don't have the same > destination_id. If I where you, i would use the temporal data typ ;-) It's a new extension for PostgreSQL, see here: http://temporal.projects.postgresql.org/reference.html, http://thoughts.j-davis.com/2010/09/25/exclusion-constraints-are-generalized-sql-unique/ http://www.slideshare.net/pgconf/not-just-unique-exclusion-constraints Regards, Andreas -- Really, I'm not out to destroy Microsoft. That will just be a completely unintentional side effect. (Linus Torvalds) "If I was god, I would recompile penguin with --enable-fly." (unknown) Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889° -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
