[AccessD] Tree shaped reports: Joe Celco BOM

Bruce Bruen bbruen at bigpond.com
Tue Jul 15 08:21:23 CDT 2003


Gustav, 

You must be psychic!  I was just retrieving the db that I used the
previous stuff in to apply again today in a new explosion situation.

Regarding maintainance of the nested set stuff,  its actually quite easy
once you have the insertion and deletion rules stated as alorithms
(psuedo code) as the pointer handling is very standard.

I have these algotithms somewhere!!!! They were in the course notes from
my university course on data structures.  Unfortunately, where somewhere
is is not handy.  I think they are at my mums place(?) I will look for
them when next I am there, which could be tomorrow or could be next
month.

Regards
Bruce

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Gustav Brock
Sent: Tuesday, 15 July 2003 8:43 PM
To: AccessD at databaseadvisors.com
Subject: Re: [AccessD] Tree shaped reports: Joe Celco BOM


Hi Bruce And Arthur

Just located this link with the Access 2000 example database:

  http://www.mvps.org/access/queries/qry0023.htm

for the nested tree lookup without recursion.

In addition to the link below:

  http://www.dbmsmag.com/9603d06.html

these deals with the topic too:

  http://www.dbmsmag.com/9604d06.html
  http://www.dbmsmag.com/9605d06.html

While the idea of a nested tree and pure SQL is nice, maintenance seems
a bit difficult ...

/gustav


> Gustav!

> You're worth bottling mate!  It worked like a charm (after a slight 
> change to cope with multiple "root" nodes).  Please find firstborn 
> male child attached as a token of my thanks.

> And thanks to everyone else for input on this topic! - except maybe 
> Charlotte who has now got me reading MSDN data shaping doco's :-)

> And Arthur, at your suggestion I have just read several of Joe Celko's

> articles available online, in particular 
> http://www.dbmsmag.com/9603d06.html
> discussing the nested-set tree model.  Strange, I learnt all about
this in
> Grad School in 1975 - don't know how I could have forgotten
it....hahaha.

> Thanks to all again!
> Bruce

> -----Original Message----- Gustav's RecursiveLookup function 
> ..(snipped)

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