That's not quite true Dan, you can join one table to another. Select
ParentID from Contacts t1, left outer join ChildID from Contacts t2
where t1.ParentID = t2.ParentID.
Cannot try it right now - my system just ate my R:Base but I have done
this sort of thing in the past.
Albert
On 15/03/2012 11:33 AM, Dan Goldberg wrote:
The problem is rbase cannot join tables to itself and does not recurse
itself.. That is why you have to use nested cursors.
Dan Goldberg
*From:* Ben Petersen <mailto:[email protected]>
*Sent:* Thursday, March 15, 2012 10:18 AM
*To:* RBASE-L Mailing List <mailto:[email protected]>
*Subject:* [RBASE-L] - Re: Exploding BOM
I looked a little further, this link is much better with examples and
code.
http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/
On Thu, Mar 15, 2012 at 9:36 AM, Ben Petersen <[email protected]
<mailto:[email protected]>> wrote:
Karen,
Take a look a "nested sets".
http://en.wikipedia.org/wiki/Nested_set_model
http://www.sqlteam.com/article/more-trees-hierarchies-in-sql
It takes a minute or two to wrap your head around, but is an
elegant solution (I think) to what you're proposing -- with
unlimited levels. No cursors, but could be write intensive if that
is a concern, though I wouldn't imagine any more than a cursor loop.
Ben
On Thu, Mar 15, 2012 at 8:55 AM, <[email protected]
<mailto:[email protected]>> wrote:
Dan: That's the way I was going to go, a definite number of
cursors. I feel
better knowing that at least one person did it in that
manner! I'll give it a while
and if no one has code for unlimited levels, then I'll just go
with that. Thanks!
Karen
In a message dated 3/15/2012 10:44:55 AM Central Daylight
Time, [email protected] <mailto:[email protected]> writes:
I use cursors. I just set up for expected level of boms that
we could possibly imagine using. We only go to a max of 6
levels down into the bom so I put in 8 cursor levels to just
in case and put an error message if it finds something below
8 levels so I can add more someday.
I know Rbase does not support celko’s nested boms so I use
cursors instead.
Dan
