Dealing with parents and children in databases

[eluser]esra[/eluser]
I believe you're describing the Adjacency List Model where recursion is used to handle hierarchies of data. See if this article helps:

http://www.sitepoint.com/article/hierarc...a-database

The other approach to managing hierachies mentioned in the article is the nested sets model. Thunder has posted a nice model and sample application on the wiki:

http://codeigniter.com/wiki/Nested_sets/

There are advantages and disadvantages of using both models.