Rails - Aug 2009 - acts_as_list / acts_as_tree / acts_as_nested_set - which one

I am creating forum application which needs usage of acts_as_list or
acts_as_tree or acts_as_nested_set.

I am unable to decide among these.  please could some one recommend from
their experience?
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Rails List wrote:
> I am creating forum application which needs usage of acts_as_list or
> acts_as_tree or acts_as_nested_set.
> 
> I am unable to decide among these.  please could some one recommend from
> their experience?
Don''t use acts_as_tree -- its data structure is simple but inefficient 
for querying.  Use awesome_nested_set instead.  Depending on what
you''re
doing, acts_as_list may be useful as well (and it works in conjunction 
with awesome_nested_set).

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
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Marnen Laibow-Koser wrote:
> Rails List wrote:
>> I am creating forum application which needs usage of acts_as_list or
>> acts_as_tree or acts_as_nested_set.
>> 
>> I am unable to decide among these.  please could some one recommend
from
>> their experience?
> 
> Don''t use acts_as_tree -- its data structure is simple but
inefficient
> for querying.  Use awesome_nested_set instead.  Depending on what
you''re
> doing, acts_as_list may be useful as well (and it works in conjunction 
> with awesome_nested_set).
> 
> Best,
> --
> Marnen Laibow-Koser
> http://www.marnen.org
> marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
Thanks Marnen, I have had a look at awesome_nested_set. It follows the 
Rails Plugin tradition of not having sufficient tutorial that a beginner 
can understand. Could you recommend some tutorial for 
awesome_nested_set?

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Rails List wrote:
[...]
> Thanks Marnen, I have had a look at awesome_nested_set. It follows the 
> Rails Plugin tradition of not having sufficient tutorial that a beginner 
> can understand. Could you recommend some tutorial for 
> awesome_nested_set?
No, because I don''t know of one either.  But the rdoc is pretty good 
(you may need to build it yourself, though).  Reading some general 
articles on nested sets might help too.

Honestly, tutorials are great, but if you need them for everything you 
do, you''re not going to get very far.
> 
> Craigslist Clone
> www.railslist.com
Best,
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http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
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It does have a tutorial somewhere in Wiki section of github, as long as 
I remember.

But all you really need is to install it, declare :lft, :rgt, and 
:parent_id in the migration, and put act_as_nested_set in the model. Not 
hard at all.
However, note that you should recreate all the existing instances of the 
model, so that :lft and :rgt fields will be set.

Cheers,
Gleb

P.S.: From my code:

class MakePlaylistsNested < ActiveRecord::Migration
  def self.up
    add_column :playlists, :parent_id, :integer
    add_column :playlists, :lft, :integer
    add_column :playlists, :rgt, :integer
  end

  def self.down
    remove_column :playlists, :parent_id, :lft, :rgt
  end
end

class Playlist < ActiveRecord::Base
  acts_as_nested_set :scope => :user_id, :depenendent => :destroy
...
end
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On Aug 19, 12:18 pm, Gleb Mazovetskiy <rails-mailing-l...@andreas-
s.net> wrote:
> It does have a tutorial somewhere in Wiki section of github, as long as
> I remember.
>
> But all you really need is to install it, declare :lft, :rgt, and
> :parent_id in the migration, and put act_as_nested_set in the model. Not
> hard at all.
Right.
> However, note that you should recreate all the existing instances of the
> model, so that :lft and :rgt fields will be set.
That''s unnecessary.  You can just walk the tree and set them
appropriately (this is best done in the migration).  Or even easier,
just call Model.rebuild! .  See http://bit.ly/gVr7Q .
>
> Cheers,
> Gleb
Best,
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Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org

Are these acts_as_* are external plugins or are they built in with 
active record?
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Rails List wrote:
> Are these acts_as_* are external plugins or are they built in with 
> active record?
They''re gems and plugins that you''ll have to install.  I think
acts_as_list and acts_as_tree used to be part of AR, but they no longer 
are.

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
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Marnen Laibow-Koser wrote:
> Rails List wrote:
>> Are these acts_as_* are external plugins or are they built in with 
>> active record?
> 
> They''re gems and plugins that you''ll have to install.  I
think
> acts_as_list and acts_as_tree used to be part of AR, but they no longer 
> are.
> 
> Best,
> --
> Marnen Laibow-Koser
> http://www.marnen.org
> marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
downloaded awsome plugin. created a table forum with parent_id, lft, rgt 
and comments.  generated scaffold for forum

now i am able to insert parent items ( ie whose parent_id is null).  How 
do I insert a child?.
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Create the item, and then use item.move_to_child_of(parent) method.
Manual: 
http://wiki.github.com/collectiveidea/awesome_nested_set/awesome-nested-set-cheat-sheet
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Gleb Mazovetskiy wrote:
> Create the item, and then use item.move_to_child_of(parent) method.
> Manual: 
>
http://wiki.github.com/collectiveidea/awesome_nested_set/awesome-nested-set-cheat-sheet
Superb Thank you

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