On Tue, 2009-07-07 at 13:22 -0400, Tom Lane wrote: > ALTER TABLE tab ADD CONSTRAINT UNIQUE (col1, col2) USING index
This would be very useful, though perhaps only because we do not have REINDEX CONCURRENTLY. It is likely to be useful in the future to allow an index with N columns, yet which can provide uniqueness with < N of those columns. This capability is known as covered indexes and will be important if Heikki writes his index-only scan code. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
