# Having trouble listing tiers of categories **URL:** \ **Category:** Rails\ **Created:** [June 17, 2006, 7:01am UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668 "2006-06-17T07:01:16Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![jpigford](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b5a626/32.png) [@jpigford](https://www.ruby-forum.com/u/jpigford)\ **Post date:** [June 17, 2006, 7:01am UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668/1 "2006-06-17T07:01:16Z")
I have categories and sub-categories in a table called “categories”. Every row has a “parent” field to note if the entry is the sub-category of another (never goes deeper than 1 level). So there might be something like this: id | name | parent 1 Dog 0 2 Pug 1 3 Siamese 5 4 Shih Tzu 1 5 Cat 0 6 Wiener Dog 1 7 Persian 5 I’d like to list it like Dog –Pug –Shih Tzu –Wiener Dog Cat –Siamese –Persian Right now it’s only listing them in one long list. But I’d like to list each parent category and have the subcats listed under them. Any ideas? ---
**Author:** ![jpigford](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b5a626/32.png) [@jpigford](https://www.ruby-forum.com/u/jpigford)\ **Post date:** [June 17, 2006, 7:16am UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668/2 "2006-06-17T07:16:38Z")
Josh P. wrote: > 4 Shih Tzu 1 > Cat > –Siamese > –Persian > > Right now it’s only listing them in one long list. But I’d like to list > each parent category and have the subcats listed under them. > > Any ideas? If you can I would recommend redoing your db and models so that you have categories and sub\_categories. That would make this really easy. All you would need to do is setup a category has\_many :sub\_categories and rails would basically do the rest for you. For instance if you setup the association then you could put this in a view (set @categories = Category.find(:all) in your controller) \<%for category in @categories%\> \<%for sub in category.sub\_categories%\> \<%=sub.name%\> \<%end%\> \<%end%\> Check out [http://rails.rubyonrails.com/classes/ActiveRecord/Associations/ClassMethods.html](http://rails.rubyonrails.com/classes/ActiveRecord/Associations/ClassMethods.html) for more info on associations. Matthew M. [blog.mattmargolis.net](http://blog.mattmargolis.net) ---
**Author:** ![jpigford](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b5a626/32.png) [@jpigford](https://www.ruby-forum.com/u/jpigford)\ **Post date:** [June 17, 2006, 9:32am UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668/3 "2006-06-17T09:32:54Z")
On Jun 16, 2006, at 10:01 PM, Josh P. wrote: > 3 Siamese 5 > > Cat > –Siamese > –Persian > > Right now it’s only listing them in one long list. But I’d like to > list > each parent category and have the subcats listed under them. Recursion is the best way I know of to handle these things. Here’s something that shows a tree correctly in text, I’ll leave it to you to convert the output to HTML, I think I’d choose nested lists. This code is called via: ShowOrganizations.as\_tree class ShowOrganizations def self.as\_tree show Organization.find\_by\_name(‘Root’),0 end ``` def self.show(organization,level) indent = ' ' * level puts indent + 'org:' + organization.name organization.children.each { |o| show o,level + 1 } end ``` end Additionally, if you want something pre-manufactured with AJAX goodness, check out the LiveTree system. [http://www.epiphyte.ca/code/live\_tree.html](http://www.epiphyte.ca/code/live_tree.html) – – Tom M. ---
**Author:** ![jpigford](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b5a626/32.png) [@jpigford](https://www.ruby-forum.com/u/jpigford)\ **Post date:** [June 17, 2006, 9:30pm UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668/4 "2006-06-17T21:30:56Z")
Matthew M. wrote: > Josh P. wrote: > > > 4 Shih Tzu 1 > > Cat > > –Siamese > > –Persian > > > > Right now it’s only listing them in one long list. But I’d like to list > > each parent category and have the subcats listed under them. > > > > Any ideas? > > If you can I would recommend redoing your db and models so that you have > categories and sub\_categories. That would make this really easy. All > you would need to do is setup a category has\_many :sub\_categories and > rails would basically do the rest for you. > For instance if you setup the association then you could put this in a > view (set @categories = Category.find(:all) in your controller) > \<%for category in @categories%\> > \<%for sub in category.sub\_categories%\> > \<%=sub.name%\> > \<%end%\> > \<%end%\> Nice. That worked…sort of. Do new controller/helpers/views need to be created? I can’t figure out how I might could keep using the same ones. ---
**Author:** ![jpigford](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b5a626/32.png) [@jpigford](https://www.ruby-forum.com/u/jpigford)\ **Post date:** [August 27, 2007, 9:25am UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668/5 "2007-08-27T09:25:26Z")
Josh P. wrote: > I have categories and sub-categories in a table called “categories”. > Every row has a “parent” field to note if the entry is the sub-category > of another (never goes deeper than 1 level). > > So there might be something like this: > > id | name | parent > 1 Dog 0 > 2 Pug 1 > 3 Siamese 5 > 4 Shih Tzu 1 > 5 Cat 0 > 6 Wiener Dog 1 > 7 Persian 5 > > I’d like to list it like > Dog > –Pug > –Shih Tzu > –Wiener Dog > > Cat > –Siamese > –Persian > > Right now it’s only listing them in one long list. But I’d like to list > each parent category and have the subcats listed under them. > > Any ideas? I am having exact same problem – I have been searching, asking, begging for weeks…but have yet to see a good way to handle the selection of a category. [http://tinyurl.com/28krhc](http://tinyurl.com/28krhc) #=\> how do I do this with rails? (eBay category selection). I’m building a store and when I edit a product, i want to easily select its category…which could be a sub-category, etc.etc. ---
**Author:** ![jpigford](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/b5a626/32.png) [@jpigford](https://www.ruby-forum.com/u/jpigford)\ **Post date:** [June 19, 2006, 8:13am UTC](https://www.ruby-forum.com/t/having-trouble-listing-tiers-of-categories/63668/6 "2006-06-19T08:13:45Z")
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sat, Jun 17, 2006 at 07:01:16AM +0200, Josh P. wrote: > I have categories and sub-categories in a table called “categories”. > Every row has a “parent” field to note if the entry is the sub-category > of another (never goes deeper than 1 level). > > So there might be something like this: > > id | name | parent Rename the ‘parent’ column to ‘parent\_id’. Your model: class Category \< ActiveRecord::Base acts\_as\_tree :order =\> :name end See the following URL for usage info, it’ll do all you want: [http://wiki.rubyonrails.com/rails/pages/ActsAsTree](http://wiki.rubyonrails.com/rails/pages/ActsAsTree) You shouldn’t use the “sub-categories” solution suggested because you’d have two nearly-identical models you’d have to keep in sync and other such pain. Keep your code nice and general. * * * Peter H. - [http://push.cx](http://push.cx) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) Comment: If you don’t know what this is, it’s OK to ignore it. iD8DBQFElj/sa6PWv6+ALKoRAu/UAJ9AG3Oio+jXvakpJZbrsf6VT5QGGwCeNtCk gBx8V0Xz20Px3zyBOehWfGs= =nZGf -----END PGP SIGNATURE-----