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Paul Barry

2006-Jan-12 06:14 UTC

[Rails] How do you create a tree strucutre with ActiveRecord

I want to build an application that has the concept of administrative
domains. What I mean by this is that administrators have access to
different data, based on what domains they are a member of. The domain
strucutre is hierarchical. Here is an example:

- MLB
- AL
- East
- Yankees
- Red Sox
...
+ Central
+ West
- NL
+ East
+ Central
+ West

Now image I could put users at any level of the domain, possibly even at
multple levels. If the user has administrative privleges, the user would be
able to edit the user accounts for other users in there domain, but not
users in other domains. So, Derek Jeter would be a user in the Yankees
domain, George Steinbrenner and admin user in the Yankees domain, David
Ortiz a user in the Red Sox domain, and Bud Selig an admin user in the MLB
domain. Since Ortiz and Jeter are just non-admin users, they can''t
edit any
other user accounts. Since steinbrenner is ad admin user in the Yankees
domain, he can edit Jeter''s account, but not Ortiz''s, because
Ortiz is not
in Steinbrenner''s domain. Bud Selig could edit both Jeter and
Ortiz''s
account, because they are in sub-domains of his domain.

The database structure would have to look something like this:

Table: Domains
+----+-----------+---------+
| id | parent_id | name |
+----+-----------+---------+
| 1 | NULL | MLB |
| 2 | 1 | AL |
| 3 | 2 | East |
| 4 | 3 | Yankees |
| 5 | 3 | Red Sox |
+----+-----------+---------+

parent_id is a FK to another domain id. A NULL parent_id indicates it is a
top-level domain. So there would be a users and a domain_users table, and
Domain model object would have a has_many_and_belongs_to_many relationship
with users. But the problem is that would only allow me to query what users
are directly in a given domain. In order to determine what users are in a
given domain, you have to include the child domains has well. So what users
are in domain MLB? The query would be:

SELECT * from domain_users where domain_id IN (1,2,3,4,5)

Then for steinbrenner it would be:

SELECT * from domain_users where domain_id IN (3)

But how do you write a query to know what child, grandchild, etc domains to
use?
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M Daggett

2006-Jan-12 06:23 UTC

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[Rails] How do you create a tree strucutre with ActiveRecord

Hi the easiest way is ...drum roll ......

acts_as_tree:

http://api.rubyonrails.com/classes/ActiveRecord/Acts/Tree/ClassMethods.html

hope that helps.
Mark

On 1/11/06, Paul Barry <mail@paulbarry.com> wrote:> I want to build an application that has the concept of administrative
> domains.  What I mean by this is that administrators have access to
> different data, based on what domains they are a member of.  The domain
> strucutre is hierarchical.  Here is an example:
>
> - MLB
>   - AL
>      - East
>       - Yankees
>        - Red Sox
>        ...
>      + Central
>      + West
>    - NL
>      + East
>      + Central
>      + West
>
>  Now image I could put users at any level of the domain, possibly even at
> multple levels.  If the user has administrative privleges, the user would
be
> able to edit the user accounts for other users in there domain, but not
> users in other domains.  So, Derek Jeter would be a user in the Yankees
> domain, George Steinbrenner and admin user in the Yankees domain, David
> Ortiz a user in the Red Sox domain, and Bud Selig an admin user in the MLB
> domain.  Since Ortiz and Jeter are just non-admin users, they
can''t edit any
> other user accounts.  Since steinbrenner is ad admin user in the Yankees
> domain, he can edit Jeter''s account, but not Ortiz''s,
because Ortiz is not
> in Steinbrenner''s domain.  Bud Selig could edit both Jeter and
Ortiz''s
> account, because they are in sub-domains of his domain.
>
>  The database structure would have to look something like this:
>
>  Table: Domains
>  +----+-----------+---------+
>  | id | parent_id | name    |
>  +----+-----------+---------+
>  |  1 |      NULL | MLB     |
>  |  2 |         1 | AL      |
>  |  3 |         2 | East    |
>  |  4 |         3 | Yankees |
>  |  5 |         3 | Red Sox |
>  +----+-----------+---------+
>
>  parent_id is a FK to another domain id.  A NULL parent_id indicates it is
a
> top-level domain.  So there would be a users and a domain_users table, and
> Domain model object would have a has_many_and_belongs_to_many relationship
> with users.  But the problem is that would only allow me to query what
users
> are directly in a given domain.  In order to determine what users are in a
> given domain, you have to include the child domains has well.  So what
users
> are in domain MLB?  The query would be:
>
>  SELECT * from domain_users where domain_id IN (1,2,3,4,5)
>
>  Then for steinbrenner it would be:
>
>  SELECT * from domain_users where domain_id IN (3)
>
>  But how do you write a query to know what child, grandchild, etc domains
to
> use?
>
>
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>

--
--------------------------------------------------------------------
I am Mark Daggett and I approve this message.

Kevin Olbrich

2006-Jan-12 06:27 UTC

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[Rails] Re: How do you create a tree strucutre with ActiveRecord

Sounds like you are looking for ''acts_as_tree''

Basically you define a model table like this..

id  parent_id  other_stuff  models_count
--  ---------  -----------  ------------

then in your model

class Model < AR::Base
 acts_as_tree :order=>"other_stuff", :counter_cache=>true
end

then you can do all sorts of fun stuff like

model.children
model.parents
model.ancestors
model.siblings

The counter cache will keep the ''models_count'' column up to
date with
the number of children, so you only need one query for that information.

_Kevin

-- 
Posted via http://www.ruby-forum.com/.

Ken Kousen

2006-Jan-12 14:59 UTC

head link

[Rails] How do you create a tree strucutre with ActiveRecord

Actually, the biggest problem you have is that you listed the Yankees ahead
of the Red Sox. :-)

 

Ken

 

--

Kenneth A. Kousen, Ph.D.

President

Kousen IT, Inc.

 <http://www.kousenit.com> http://www.kousenit.com

 <mailto:ken.kousen@kousenit.com> ken.kousen@kousenit.com 

  _____  

From: rails-bounces@lists.rubyonrails.org
[mailto:rails-bounces@lists.rubyonrails.org] On Behalf Of Paul Barry
Sent: Thursday, January 12, 2006 1:14 AM
To: rails@lists.rubyonrails.org
Subject: [Rails] How do you create a tree strucutre with ActiveRecord

 

I want to build an application that has the concept of administrative
domains.  What I mean by this is that administrators have access to
different data, based on what domains they are a member of.  The domain
strucutre is hierarchical.  Here is an example:

- MLB
  - AL
    - East
      - Yankees
      - Red Sox
      ...
    + Central
    + West
  - NL
    + East
    + Central
    + West

Now image I could put users at any level of the domain, possibly even at
multple levels.  If the user has administrative privleges, the user would be
able to edit the user accounts for other users in there domain, but not
users in other domains.  So, Derek Jeter would be a user in the Yankees
domain, George Steinbrenner and admin user in the Yankees domain, David
Ortiz a user in the Red Sox domain, and Bud Selig an admin user in the MLB
domain.  Since Ortiz and Jeter are just non-admin users, they can''t
edit any
other user accounts.  Since steinbrenner is ad admin user in the Yankees
domain, he can edit Jeter''s account, but not Ortiz''s, because
Ortiz is not
in Steinbrenner''s domain.  Bud Selig could edit both Jeter and
Ortiz''s
account, because they are in sub-domains of his domain.

The database structure would have to look something like this:

Table: Domains
+----+-----------+---------+
| id | parent_id | name    |
+----+-----------+---------+
|  1 |      NULL | MLB     |
|  2 |         1 | AL      |
|  3 |         2 | East    |
|  4 |         3 | Yankees |
|  5 |         3 | Red Sox |
+----+-----------+---------+

parent_id is a FK to another domain id.  A NULL parent_id indicates it is a
top-level domain.  So there would be a users and a domain_users table, and
Domain model object would have a has_many_and_belongs_to_many relationship
with users.  But the problem is that would only allow me to query what users
are directly in a given domain.  In order to determine what users are in a
given domain, you have to include the child domains has well.  So what users
are in domain MLB?  The query would be:

SELECT * from domain_users where domain_id IN (1,2,3,4,5)

Then for steinbrenner it would be:

SELECT * from domain_users where domain_id IN (3)

But how do you write a query to know what child, grandchild, etc domains to
use?





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Peter Ertl

2006-Jan-12 15:52 UTC

head link

[Rails] How do you create a tree strucutre with ActiveRecord

acts_as_tree in ActiveRecord works very well for me

read "Agile Web Development in Rails" for more information


> --- Urspr?ngliche Nachricht ---
> Von: "Ken Kousen" <ken.kousen@kousenit.com>
> An: <rails@lists.rubyonrails.org>
> Betreff: RE: [Rails] How do you create a tree strucutre with ActiveRecord
> Datum: Thu, 12 Jan 2006 09:59:03 -0500
> 
> Actually, the biggest problem you have is that you listed the Yankees
> ahead
> of the Red Sox. :-)
> 
>  
> 
> Ken
> 
>  
> 
> --
> 
> Kenneth A. Kousen, Ph.D.
> 
> President
> 
> Kousen IT, Inc.
> 
>  <http://www.kousenit.com> http://www.kousenit.com
> 
>  <mailto:ken.kousen@kousenit.com> ken.kousen@kousenit.com 
> 
>   _____  
> 
> From: rails-bounces@lists.rubyonrails.org
> [mailto:rails-bounces@lists.rubyonrails.org] On Behalf Of Paul Barry
> Sent: Thursday, January 12, 2006 1:14 AM
> To: rails@lists.rubyonrails.org
> Subject: [Rails] How do you create a tree strucutre with ActiveRecord
> 
>  
> 
> I want to build an application that has the concept of administrative
> domains.  What I mean by this is that administrators have access to
> different data, based on what domains they are a member of.  The domain
> strucutre is hierarchical.  Here is an example:
> 
> - MLB
>   - AL
>     - East
>       - Yankees
>       - Red Sox
>       ...
>     + Central
>     + West
>   - NL
>     + East
>     + Central
>     + West
> 
> Now image I could put users at any level of the domain, possibly even at
> multple levels.  If the user has administrative privleges, the user would
> be
> able to edit the user accounts for other users in there domain, but not
> users in other domains.  So, Derek Jeter would be a user in the Yankees
> domain, George Steinbrenner and admin user in the Yankees domain, David
> Ortiz a user in the Red Sox domain, and Bud Selig an admin user in the MLB
> domain.  Since Ortiz and Jeter are just non-admin users, they
can''t edit
> any
> other user accounts.  Since steinbrenner is ad admin user in the Yankees
> domain, he can edit Jeter''s account, but not Ortiz''s,
because Ortiz is not
> in Steinbrenner''s domain.  Bud Selig could edit both Jeter and
Ortiz''s
> account, because they are in sub-domains of his domain.
> 
> The database structure would have to look something like this:
> 
> Table: Domains
> +----+-----------+---------+
> | id | parent_id | name    |
> +----+-----------+---------+
> |  1 |      NULL | MLB     |
> |  2 |         1 | AL      |
> |  3 |         2 | East    |
> |  4 |         3 | Yankees |
> |  5 |         3 | Red Sox |
> +----+-----------+---------+
> 
> parent_id is a FK to another domain id.  A NULL parent_id indicates it is
> a
> top-level domain.  So there would be a users and a domain_users table, and
> Domain model object would have a has_many_and_belongs_to_many relationship
> with users.  But the problem is that would only allow me to query what
> users
> are directly in a given domain.  In order to determine what users are in a
> given domain, you have to include the child domains has well.  So what
> users
> are in domain MLB?  The query would be:
> 
> SELECT * from domain_users where domain_id IN (1,2,3,4,5)
> 
> Then for steinbrenner it would be:
> 
> SELECT * from domain_users where domain_id IN (3)
> 
> But how do you write a query to know what child, grandchild, etc domains
> to
> use?
> 
> 
> 
> 
> 
>

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