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Re: transitive closure

From: Mikito Harakiri <mikharakiri_nospaum_at_yahoo.com>
Date: 19 Jul 2005 09:58:12 -0700
Message-ID: <1121792292.394791.182540@o13g2000cwo.googlegroups.com>


Marshall Spight wrote:
> Marshall Spight wrote:
> >
> > What about TTM's proposed TCLOSE?
> >
> > What about a Prolog-like solution?
> >
> > What about recursive queries?
>
> Anyone have any experience with Oracle's CONNECT BY?
> Is it the right abstraction? Too narrow? Too broad?
> Does it work well?

It's a hack that happens to work OK. One question that has been repeatedly asked (but didn't seem to trigger much of an interest) is whether its expresive power is equivalent to recursive "with". The latter has an advantage more easily extending the relation with new pseudocolumns. Look at this integer generator, for example

with Integers (num) as
( values(1)
  union all
  select num+1 from Integers
  where num < 100
)
select * from Integers

There is a zillion of ways to generate integers in oracle, and I yet to see a case that is handled by recursive "with" and not handled by "connect by". Received on Tue Jul 19 2005 - 11:58:12 CDT

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