Nested Sets AKA Modified Pre-order Tree Traversal

http://upload.wikimedia.org/wikipedia/commons/thumb/4/41/NestedSetModel.svg/400px-NestedSetModel.svg.png

http://en.wikipedia.org/wiki/Nested_set_model

SQLAlchemy-ORM-Tree:

An implementation for SQLAlchemy-based applications of the nested-sets/modified-pre-order-tree-traversal technique for storing hierarchical data in a relational database.

https://github.com/monetizeio/sqlalchemy-orm-tree/

Introducing SQLAlchemy-ORM-tree: a generic API for hierarchical data : https://groups.google.com/forum/?fromgroups#!topic/sqlalchemy/GIMq_Y6_bP4

http://pypi.python.org/pypi/SQLAlchemy-ORM-tree

Utilities for implementing a modified pre-order traversal tree in django.: https://github.com/django-mptt/django-mptt

Root Node: Left value of 1, right value equal to 2*(# of nodes)

Nested Sets Using Indexed Rational Numbers

For each ancestor node,

LVanc < LVme < RVme < RVanc

For each descendant node,

LVme < LVdesc < RVdesc < RVme

Moving nested set nodes without save/delete/insert: http://www.sitepoint.com/forums/mysql-182/move-nested-set-node-700826.html

http://blog.stannard.net.au/nested-set-trees/nested-set-trees-objects/

[BLOG] Help! My Hierarchy is Slow – Faster Hierarchies with Nested Sets Aug 3 2007: http://kylecordes.com/2007/nested-sets

http://en.wikipedia.org/wiki/Nested_set_model

http://code.google.com/p/django-mptt/source/browse/trunk/NOTES

http://code.google.com/p/django-mptt/source/browse/trunk/mptt/utils.py#29

http://halestock.wordpress.com/2010/02/04/symfony-implementing-a-nested-set-part-three/

http://www.sqlalchemy.org/trac/browser/examples/nested_sets/nested_sets.py

http://www.ibase.ru/devinfo/DBMSTrees/9604d06.html (orig) http://replay.web.archive.org/20080517111145/http://www.dbmsmag.com/9604d06.html

http://datamapper.wanwizard.eu/pages/extensions/nestedsets.html

http://www.edutech.ch/contribution/nstrees/index.php

http://blog.stannard.net.au/nested-set-trees/nested-set-trees-objects/

http://www.codeproject.com/KB/database/nestedsets.aspx?msg=2301676

http://stackoverflow.com/questions/889527/mysql-move-node-in-nested-set

http://archives.postgresql.org//pgsql-sql/2002-11/msg00358.php

http://stackoverflow.com/questions/1602536/mysql-nested-sets-how-to-find-parent-of-node

http://stackoverflow.com/questions/662697/id-like-to-use-the-nested-set-model-but-im-obliged-to-have-a-guid-as-primary

http://forums.mysql.com/read.php?20,365735

http://www.fliquidstudios.com/2008/12/23/nested-set-in-mysql/

http://www.sqlteam.com/article/more-trees-hierarchies-in-sql

http://blogs.sitepoint.com/hierarchical-data-database-2/

http://stackoverflow.com/questions/316267/help-with-writing-a-sql-query-for-nested-sets

http://dba.fyicenter.com/article/Trees-in-SQL.html

http://stackoverflow.com/questions/1974541/mysql-nested-set-model-searching-in-nodes

http://stackoverflow.com/questions/319108/building-hierarchy-objects-from-flat-list-of-parent-child

http://stackoverflow.com/questions/894077/sql-query-to-avoid-fetching-the-entire-nested-set-when-parts-of-it-are-collapsed

http://mysql.bigresource.com/How-to-move-nested-set-subtrees--ZK1reKLW.html

http://stackoverflow.com/questions/4143014/allow-multiple-categories-with-the-same-name-with-a-nested-set-structure

http://halestock.wordpress.com/2010/02/04/symfony-implementing-a-nested-set-part-three/

http://www.ibase.ru/devinfo/DBMSTrees/9604d06.html

http://getabest.net/get/nested-sets-db-tree/?q=nested-sets-db-tree

http://www.logarithmic.net/pfh/blog/01235197474

http://www.codeproject.com/KB/database/nestedsets.aspx

http://www.kamfonas.com/id3.html

http://stackoverflow.com/questions/5725914/mysql-recursive-tree-search

http://roojs.com/blog.php/View/179/nested%20trees%20in%20mysql%20-%20handy%20stored%20procedures

http://explainextended.com/2009/09/29/adjacency-list-vs-nested-sets-mysql/