understanding database table ps_category

[pei7]

Hallo,

 

I have recently installed Prestashop 1.5.4.1. Currently I am trying to understand how prestashop stores the category on the database level.

 

Looking into the table ps_category, there are the following columns:

- id_category

- id_parent

- id_shop_default

- level_depth

- nleft

- nright

- active

- date_add

- date_upd

- position

- is_root_category

 

Would somebody please explain me briefly what the column 'position' is used for?

 

Thank you very much.