Re: Nested Sets vs. Nested Intervals
Date: 9 Nov 2005 13:08:02 -0800
> Thank you very much, Vadim Tropashko.
> Nested Intervals are very efficient for updating and selecting
> hierarchical categories. I am creating a web application/directory from
> it, but it would be more convenient for the user to retrieve its
> children from an array of folder names in the URL (seperated by dots or
> slashes, like google groups does for its usenet categories) instead of
> a category_id.
> Both dmoz and yahoo also retrieves its immediate subcategories by the
> array of folder-names in the URL; Unlike some other directories that
> retrives its immediate subcategories from a category_id in the URL. Is
> there any efficient way to retrieve its immediate subcategories by an
> array of folder-names such as dmoz and yahoo?
> Basically, it's like replicating a file system: an array of folder
> names can point to the category_id to retrieve their children. However,
> it would take recursive SELECTs to find the category_id from the array
> of folder names.
So why don't you just use a simple adjacency list and a recursive query instead ? What database are you using ? Received on Wed Nov 09 2005 - 22:08:02 CET