Comments on: How Nested Sets Work

By: Barney

Barney — Tue, 20 Sep 2005 14:04:37 +0000

The TreeManager (as it says in the readme) was developed on MySQL, and makes use of the LIMIT clause, which to my knowledge, is only supported by MySQL and PostgreSQL. It's similar to the MSSQL TOP clause, though LIMIT has the ability to do an offset as well.

Porting the SQL to MSSQL should be pretty trivial, and shouldn't require a real understanding of what's going, just the ability to provide the MSSQL syntax. I believe it'll just be LIMIT to TOP conversions, but without a SQL Server to test on, I can't say for sure.

If you do port it, I'd be interested in the resulting code so I can include it in the distribution.

By: Mike Kear

Mike Kear — Tue, 20 Sep 2005 06:50:34 +0000

I followed the linke to Joe Celko's 2001 Article, which mentions a follow up article. I guessed that would explain why the code didnt work on my database, so I clicked on it to follow it. Sadly, it went nowhere. It led to SearchORacle.com, so I seached in SearchOracle.com for the follow uparticle. I couldn't get access to SearchOracle.com unless I registered, which took me 45 minutes of giving them multiple opportunities to spam me (with 2000 emails a day, mostly spam, what I Really need is yet ANOTHER "newsletter"). After all that, his Follow UP article can be found in the search engine on that site, but when you click on it, it takes you to a "page not found". AAARRRRGH!!!!!!!!!!

So the code doesnt work on SQLServer, and I still dont know why and still havent seen the followup.

(sigh).

By: Michael Conger

Michael Conger — Mon, 12 Sep 2005 15:41:21 +0000

Agreed. Joe Celko is the man all around. He lays out nested sets in great detail in his fantastic book "SQL for Smarties". I highly recommend it. My dog-eared, coffee-stained copy has been on my desk for 5yrs.

By: Barney

Barney — Sun, 11 Sep 2005 03:09:38 +0000

Yep, yep, yep. Here's a link to the tutorial I used to help me out (well, same content, different location): http://searchoracle.techtarget.com/tip/1,289483,sid13_gci537290,00.html

By: Mike Tangorre

Mike Tangorre — Sat, 10 Sep 2005 21:26:30 +0000

Barney,

I used to use the adjacency list method until running into nested sets one day at a previous job. I just wanted to mention that Joe Celko is the man when it comes to nested sets and he has some great tutorials and articles over at DB Magazine dot com (not sure of the addy.. google it).

Mike T