

Hierarchical Queries in MySQL (Function substitute for CONNECT BY) - ratsbane
http://explainextended.com/2009/03/17/hierarchical-queries-in-mysql/

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nbpoole
This is a bad way to store hierarchical data in MySQL: the performance is
terrible due to the number of queries that have to be issued. The nested set
model (<http://en.wikipedia.org/wiki/Nested_set_model>) is a better solution.

~~~
quassnoi
Sure, especially if you nest the sets using a datatype indexable with an
R-Tree index: [http://explainextended.com/2009/09/29/adjacency-list-vs-
nest...](http://explainextended.com/2009/09/29/adjacency-list-vs-nested-sets-
mysql/)

However, nested sets is still very expensive to update which may be a deciding
factor if your hierarchy is subject to frequent change (like, a folder-like
structure with the folders being moved here and there) and you don't need to
query for "all descendants" often.

