On Aug10, 2011, at 08:45 , Noah Misch wrote: > On Tue, Aug 09, 2011 at 09:41:00PM +0200, Florian Pflug wrote: >> Couldn't we simply give the user a way to specify, per column, whether or >> not that column is a "KEY" column? Creating a foreign key constraint could >> still implicitly mark all referenced columns as KEY columns, but columns >> would no longer be "KEY" columns simply because they're part of a UNIQUE >> constraint. Users would be free to add arbitrary columns to the set of >> "KEY" columns by doing ALTER TABLE ALTER COLUMN SET KEY. > > What would be the use case for manually expanding the set of key columns?
You'd use that if you implemented a FK-like constraint (e.g. a FK on an array-values field). Without a way to manually expand the set of KEY columns, such a non-core FK constraint couldn't use the lighter locks. best regards, Florian Pflug -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
