Rails - Jul 2005 - acts_as_tree and traversing parent/child relationships

I am working on an Rails application that uses a pretty complex  
category structure through out the site.  I have defined a table to  
house all the info and a FK to reference parents within the table

CREATE TABLE categories (
   id int(11) NOT NULL auto_increment,
   name varchar(50) NOT NULL,
   parent_id int(11) default NULL,
   constraint fk_category_id foreign key (category_id) references  
categories(id),
   PRIMARY KEY  (id)
);

My goal was to be able to set the names to reference other entries in  
the table, establishing the parent/child relationship

parent = id: 1 name: Category 1 parent_id: NULL
child = id: 2 name: child 1 parent_id: 1
child = id: 3 name: child 2 parent_id: 2

My Model starts out as:

class Category < ActiveRecord::Base
     acts_as_tree :order => "name"

     belongs_to :catagory, :class_name => "Category", :foreign_key
=>
"parent_id"
     has_many :sub_category, :class_name => "Category",
:foreign_key
=> "parent_id"

Which seems right

I know that acts_as_nested_set has the ability to traverse through  
the structure but everything I hear says not to use it yet.  My  
question is more or less can I till use it''s methods?  Should I?  Or  
would the best practice be to write a helper for this?

I am a bit new to Rails but this is really stumping me, or maybe I''m  
looking a bit to hard into it.

J Brien | HybridIndie Productions | hybridindie.com |  
iam-QLwuMy0vUAhCl22TKe+ceQ@public.gmane.org

The nested_set approach will require a different schema: you need left and 
right indicators. The good news is that you will not need the belongs to and 
all that, it''s just a tree.

Hope it helps,


Adrian Madrid


On 7/25/05, J Brien <iam-QLwuMy0vUAhCl22TKe+ceQ@public.gmane.org>
wrote:
> 
> I am working on an Rails application that uses a pretty complex
> category structure through out the site. I have defined a table to
> house all the info and a FK to reference parents within the table
> 
> CREATE TABLE categories (
> id int(11) NOT NULL auto_increment,
> name varchar(50) NOT NULL,
> parent_id int(11) default NULL,
> constraint fk_category_id foreign key (category_id) references
> categories(id),
> PRIMARY KEY (id)
> );
> 
> My goal was to be able to set the names to reference other entries in
> the table, establishing the parent/child relationship
> 
> parent = id: 1 name: Category 1 parent_id: NULL
> child = id: 2 name: child 1 parent_id: 1
> child = id: 3 name: child 2 parent_id: 2
> 
> My Model starts out as:
> 
> class Category < ActiveRecord::Base
> acts_as_tree :order => "name"
> 
> belongs_to :catagory, :class_name => "Category", :foreign_key
=>
> "parent_id"
> has_many :sub_category, :class_name => "Category",
:foreign_key
> => "parent_id"
> 
> Which seems right
> 
> I know that acts_as_nested_set has the ability to traverse through
> the structure but everything I hear says not to use it yet. My
> question is more or less can I till use it''s methods? Should I? Or
> would the best practice be to write a helper for this?
> 
> I am a bit new to Rails but this is really stumping me, or maybe
I''m
> looking a bit to hard into it.
> 
> J Brien | HybridIndie Productions |
hybridindie.com<http://hybridindie.com>|
> iam-QLwuMy0vUAhCl22TKe+ceQ@public.gmane.org
> 
> 
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 


-- 
Adrian Esteban Madrid
aemadrid-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org


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If you haven''t implemented a tree module yet you may want to consider 
sqltree.rb (http://rubyforge.org/frs/?group_id=835).
Full disclosure: I wrote the d*mn thing.
I use the module myself, but not with Rails (yet).
[caveat: it works best with MySQL]

-lv

J Brien wrote:
> I am working on an Rails application that uses a pretty complex  
> category structure through out the site.  I have defined a table to  
> house all the info and a FK to reference parents within the table
> 
[snip,snap,crackle,pop]
> 
> I know that acts_as_nested_set has the ability to traverse through  the 
> structure but everything I hear says not to use it yet.  My  question is 
> more or less can I till use it''s methods?  Should I?  Or  would
the best
> practice be to write a helper for this?
> 
> I am a bit new to Rails but this is really stumping me, or maybe
I''m
> looking a bit to hard into it.
> 
> J Brien | HybridIndie Productions | hybridindie.com |  
> iam-QLwuMy0vUAhCl22TKe+ceQ@public.gmane.org