The following bug has been logged on the website:
Bug reference: 7525
Logged by: Rikard Pavelic
Email address: rikard.pavelic@zg.htnet.hr
PostgreSQL version: 9.1.2
Operating system: Windows 7
Description: =
Is there a way in Postgres to create a unique constraint with predicate or
an unique index which is deferred?
Depesz said not yet.
http://www.depesz.com/2009/08/11/waiting-for-8-5-deferrable-uniqueness/
Can't find it on todo.