Add DEFERRED option to check constraints
To improve data consistency foreign keys and simple row based checks isn't always enough. Sometimes you would like to write a stored procedure that does more advanced checks. This is fine until you would like to make that advanced constraint deferred which is not possible. "Only foreign key constraints currently accept this clause. All other constraint types are not deferrable." - http://www.postgresql.org/docs/8.4/interactive/sql-createtable.html I request deferrable check constraints!
Marko Tiikkaja commented
I don't see the point of this. CHECK constraints are *NOT* supposed to be used to do any "advanced checks". That's why PG has the concept of "constraint triggers" which can already be DEFERRED.