Tree data structure in php

Question

in my application user starts a new tree or get added under a child-user and keep on adding users in branches in such a way-
>there are 10 level of tree type structure.
>root node contain 1 user and each node(user) can have max 5 child-user in this way tree will be like level 0 = 1 user ,
level 1 = 5 user,
level 2 = 25 user ,
level 3 = 125 user and so on.

I created one MySQL table having columns like-

User_id , level, super_id, child1_id, child2_id, child3_id, child4_id, child5_id

my question is How can I get all child-user(child to child also) of a particular user at any level do I need to add some more columns in my table??

Answer 1

You should have a look at Nested Sets.

In PHP, you could use Doctrine Nested Sets, that will make your life much easier.

Answer 2

You might find it interesting to read my presentation from last week's PHP TEK-X conference:

Models for Hierarchical Data with SQL and PHP

This talk describes alternative solutions in SQL, including:

• Adjacency List
• Path Enumeration
• Nested Sets
• Closure Table

Also see my answer to this Stack Overflow question: What is the most efficient/elegant way to parse a flat table into a tree?

Answer 3

why don't you create a table that contains:

table1:
id, level, users // this way you can manipulate the max users from this level

table2:
id, level, super_id // and you can set create as many as you like (tree based table)
// eg:

id1 | level0 | id0
id2 | level1 | id0
id3 | level2 | id1
id4 | level2 | id1

i hope you understand what i meant by this ..