Re: small exclusion constraints patch
Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>
From: Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Bruce Momjian <bruce@momjian.us>, Jeff Davis <pgsql@j-davis.com>, pgsql-hackers@postgresql.org
Date: 2010-05-30T10:54:17Z
Lists: pgsql-hackers
On 2010-05-30 06:55 +0300, Robert Haas wrote: > On Sat, May 29, 2010 at 11:40 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> Yes, I've seen Jeff's example. It's a cute hack but somehow I doubt >> that there is going to be a land rush to implement such things. >> Can you point to any pre-existing example where anyone actually asked >> for the ability to do that? > > I've often wished for the ability to constrain a tale to hold just one > row, so I don't find that use case implausible at all. As I pointed out in http://archives.postgresql.org/pgsql-hackers/2010-05/msg01177.php , you can already do that. Having said that, I also think that supporting <> in exclusion constraints would be useful. I can't come up with a real-world use case right now though. Regards, Marko Tiikkaja