On 20 Jun 2011, at 17:03, Tarlika Elisabeth Schmitz wrote: > I have two tables, town and townalias, the latter containing alternative > town names. > I would like to ensure that a town name is unique per > country-region across the two tables. > > Can I do this with a constraint ot do I need to implement the logic via > trigger? This is very similar to what was recently discussed in the topic "Constraint to ensure value does NOT exist in another table?" in this list. Alban Hertroys -- If you can't see the forest for the trees, cut the trees and you'll see there is no forest. !DSPAM:737,4dff868612099297279502! -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general