From: Brian Candler <B.Candler@...>
Date: 2004-10-08T23:11:42+09:00
Subject: Re: [ANN] ndb Object-Relational Mapper

On Fri, Oct 08, 2004 at 10:39:44PM +0900, George Moschovitis wrote:
> Have a look at the following link tha explains this technique:
> 
> http://www.ibase.ru/devinfo/DBMSTrees/sqltrees.html

This is a very cute data structure which I hadn't come across before.
However, if I add a new subordinate to 'Bert' (say 'Bob'), don't I end up
having to renumber almost the entire tree?

            Albert
             1,14
         /          \
     Bert            Chuck
     2,5              6,13
      |            /   |   \
     Bob     Donna   Eddie  Fred
     3,4      7,8     9,10  11,12

Example 5 in that page gives the SQL to do this, but I don't fancy updating
10 million nodes on each insert (and in an ISP, signups happen
continuously). Perhaps there is a workaround: e.g. add the nodes into a
temporary adjacency list representation, and then once a night walk the tree
to insert in bulk. I'd have to think about that.

Regards,

Brian.