How to create category?

I want to create multiple category with undefined depth.Please suggest me any tutorial or block of code which can help me.

 

Hi just use the following
catid
catname
parentid (this will point to catid)

 

thanks for your post, i know this logic but how to implement it by recursive method?

 

To get theory try google for
'nested sets php'
'materialized path php'
As far as I know these can have unlimited nested categories.

 

hi ul, I have the same problem.
Multiple categories: what you mean parentid?
catid: INT
catname: vchar
parentid: ???