On Fri, Nov 12, 2010 at 12:53:09AM -0500, Robert Haas wrote: > On Fri, Nov 12, 2010 at 12:21 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Robert Haas <robertmh...@gmail.com> writes: > >> On Thu, Nov 11, 2010 at 10:02 AM, Itagaki Takahiro > >> <itagaki.takah...@gmail.com> wrote: > >>> If we reuse type IDs of arrays for multisets, the multisets would > >>> have some special typmod. For example, typmod = 0 means multiset, > >>> and positive value means array with max cardinality. Note that > >>> the SQL standard doesn't mention about multi-dimensional arrays. > >>> So, we can use typmod = -1 as a free-size and free-dimensional > >>> array for backward compatibility. > > > >> I would really like to see us fix our type system so that it doesn't > >> require this type of awful hack. But maybe that's asking too much of > >> a patch to implement this feature. > > > > The problem is not with the type system: as long as you give multisets > > different type OIDs from arrays, everything will work fine. It will > > absolutely not work to try to use typmod to make the behavior vary > > like that ... but Itagaki-san knew that already. > > And thus you must create a THIRD copy of every entry in pg_type. That > doesn't qualify as a problem?
Yes, and I've started a separate thread on this along with a page on the wiki. Cheers, David. -- David Fetter <da...@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fet...@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
