Re: self referencing tables/ nested sets etc...

On Thursday 25 March 2004 12:19, Manfred Koizar wrote:
> On Tue, 23 Mar 2004 22:25:17 +0100, Rob Hoopman <rob(at)tuna(dot)nl> wrote:
> >What solutions are there to storing a wide/shallow self referencing tree
> > in a database?
>
> contrib/ltree (http://www.sai.msu.su/~megera/postgres/gist/ltree/) or
> Joe's connectby() might help.
That's just what I need, thanks!

>
> >( And the 'Real World Performance group at
> >Oracle Corp.' sounds like a ringing endorsement )
>
> Ok, that made me change my sig. <bg>
:-)
I should have know the Oracle Corp's 'Real World' has little or nothing to do
with my real world.

>
> > I have spent today wrestling with [...]
> > inaccuracies in the article,
>
> ^
> ... and bugs ...
That's what I was thinking, but I thought surely this Oracle dude knows better
than me.

> > It appears that when adding more than 48 sub nodes
> >to any node in the tree, craps out because of an INT8 column overflowing.
>
> AFAICS it doesn't depend on the number of siblings, but it fails when
> the sum of the numbers in dotted path notation exceeds 62.
>
Maybe, but some of the intermediate steps are larger than the number that gets
stored in the end. Actually that's where this implementation broke for me.

> <rant>
SNIP
> </rant>
Thanks, that was educational.

Cheers,
Rob