CELKO'S NESTED TREE SET

[Deleted]

Just made the move from using the adjacency list model (id, parent) to using the nested set model (id, lft, rgt).

Currently running MySQL 4.17

My goal is to create a virtual directory.

The question I have is:

Is it possible to limit the results of a SELECT to only return the next level in the tree (without the children).

http://unixjunky.com

 

[BNPMike]

Are you sure this will work? A typical directory is not a binary tree, which is what you've got.

 

[r937]

nested set model is not necessarily a binary tree

unixjunky, if all you wanted was the next level, the adjacency model is perfect for that, it's a simple self-join

otherwise, you're on your own, i know celko has published a book on his nested set model and you may need to buy it to feel comfortable with writing the sql

i know every time i've tried to understand it, i ended up spending far too much time drawing pictures and never did get as far as the sql...

rudy | r937.com | Ask the Expert | Premium SQL Articles
SQL for Database-Driven Web Sites (course starts January 9 2005)

 

[Deleted]

i know celko has published a book on his nested set model"

I got both of his books. Unfortunately almost everything relies on stored procedures which is not available on the version on MySQL I am running.

Regardless the adjacency list and nested tree set both have their limitations. It would be nice to strike a balance between the two.

Thanks,

http://unixjunky.com