I had some time during vacation to thing about postgresql. And here's the
feature I'd really like to see. This one would put us miles in front of all
others: recursive view definitions.

Just one short example:

There is that well-known parent relation: par (parent, child). The view anc
now should list all ancestors:

create view anc as
	select parent as ancestor, child as person from par
	union
	select anc.ancestor as ancestor, par.child as person
	from anc, par
	where anc.person = par.parent;

What do you guys think of this idea? How much work would it be to implement
it?

Michael
-- 
Dr. Michael Meskes, Project-Manager    | topsystem Systemhaus GmbH
meskes@topsystem.de                    | Europark A2, Adenauerstr. 20
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Thu, 16 Apr 1998 16:29:09 +0200 (CEST)
Michael Meskes <meskes@topsystem.de>
recursive views
> 
> I had some time during vacation to thing about postgresql. And here's the
> feature I'd really like to see. This one would put us miles in front of all
> others: recursive view definitions.
> 
> Just one short example:
> 
> There is that well-known parent relation: par (parent, child). The view anc
> now should list all ancestors:
> 
> create view anc as
> 	select parent as ancestor, child as person from par
> 	union
> 	select anc.ancestor as ancestor, par.child as person
> 	from anc, par
> 	where anc.person = par.parent;
> 
> What do you guys think of this idea? How much work would it be to implement
> it?

You want views of UNION's.  That is not hard to do.


-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

Thu, 16 Apr 1998 13:21:55 -0400 (EDT)
Bruce Momjian <maillist@candle.pha.pa.us>
Re: [HACKERS] recursive views
> 
> I had some time during vacation to thing about postgresql. And here's the
> feature I'd really like to see. This one would put us miles in front of all
> others: recursive view definitions.
> 
> Just one short example:
> 
> There is that well-known parent relation: par (parent, child). The view anc
> now should list all ancestors:
> 
> create view anc as
> 	select parent as ancestor, child as person from par
> 	union
> 	select anc.ancestor as ancestor, par.child as person
> 	from anc, par
> 	where anc.person = par.parent;
> 
> What do you guys think of this idea? How much work would it be to implement
> it?

Ah, you want views of UNION's, and want to specify the view in the
query.  Yikes, no idea on how hard that would be.

-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

Thu, 16 Apr 1998 13:22:32 -0400 (EDT)
Bruce Momjian <maillist@candle.pha.pa.us>
Re: [HACKERS] recursive views