From be1f8391eaa0edc34bc1c3a99ea18b43183d2ccd Mon Sep 17 00:00:00 2001
From: zYne <zYne@625475ce-881a-0410-a577-b389adb331d8>
Date: Sun, 23 Sep 2007 16:25:47 +0000
Subject: [PATCH]

---
 manual/new/docs/en/relations.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/manual/new/docs/en/relations.txt b/manual/new/docs/en/relations.txt
index 3de7295a1..00f300f2a 100644
--- a/manual/new/docs/en/relations.txt
+++ b/manual/new/docs/en/relations.txt
@@ -144,6 +144,10 @@ class Phonenumber extends Doctrine_Record
 
 +++ Tree structure
 
+A tree structure is a self-referencing foreign key relation. The following definition is also called Adjacency List implementation in terms of hierarchical data concepts. 
+
+However this mainly just serves as an example how the self-referencing can be done. The definition above is rarely a good way of expressing hierarchical data, hence you should take a look at the Hierachical data chapter for how to set up efficient parent/child relations.
+
 <code type="php">
 class Task extends Doctrine_Record 
 {