| From: | Frank Joerdens <frank(at)joerdens(dot)de> |
|---|---|
| To: | Tulassay Zsolt <zsolt(at)tek(dot)bke(dot)hu> |
| Cc: | pgsql-sql(at)postgresql(dot)org |
| Subject: | Re: Tree structure table normalization problem (do I need atrigger?) |
| Date: | 2000-12-19 13:17:58 |
| Message-ID: | 3A3F6006.ECDE92AE@joerdens.de |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-sql |
Tulassay Zsolt wrote:
[ . . . ]
> The SQL stuff of that nested set structure is fairly easy, I wrote some
> quick'n'dirty plpgsql functions that will do inserts, updates, deletes
> from the tree, display level number etc.
What scared me about it in particular was one scenario where you try to delete a subtree.
This would normally leave a gap, since the structure is based on the worm's ability to get
from one node to the next with an increment of just 1. Once you had a subtree deleted,
you'd either would have to have the worm leap-frog (a leaping frog-worm?!! :)) the gap or
update an entire half of the tree to close it . . . then my brain started to hurt and I
gave up.
> I can send it to you if you like (please allow a few days since I
> have several exams at the university this week).
Sure, I'd like to have a look at it!
Thanks, Frank
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Frank Joerdens | 2000-12-19 13:51:16 | Re: Tree structure table normalization problem (do I need atrigger?) |
| Previous Message | Brett W. McCoy | 2000-12-19 13:08:09 | Re: replace?? |