From: "Dmitry V. Sabanin" <sdmitry@...>
Date: 2004-09-27T20:02:54+09:00
Subject: [Rails] #has_and_belongs_to_many problem

Hi,

  I'm playing with Rails and I must say that it's really great framework. Web 
development was never been so easy and pleasure. However, I'm having a lot of 
small problems in understanding the New Way(TM) of creating stuff for web.

  I have a problem when I try to extend ACL example that's listed on wiki:
http://activerecord.rubyonrails.org/show/AccessControlListExample
There's model Role and Permission, Role#has_and_belongs_to_many permissions,
and everything works fine. But, when I remove a Permission that belongs to 
some Role, I still see reference to it in `permissions_roles` table. I've 
tried following code to delete all permissions from Role's that use them, but 
it doesn't work also, links to non-existant Permissions are still in 
`permissions_roles` table:

class Permission < ActiveRecord::Base
  has_and_belongs_to_many :roles
  
  def before_destroy
     Role.find_all.each do |role|
       role.permissions(true).each do |perm|
 # I'm comparing id's here because i'm not sure if 
 # ActiveRecord handles #== right
         if perm.id == read_attribute("id")
           role.remove_permissions(perm.id)
           role.save
         end
       end
     end
   end
   
end

P.S. Maybe that's a problem with me being using MySQL, which has no support 
for foreign keys in stable version?
-- 
sdmitry -=- Dmitry V. Sabanin
MuraveyLabs.
Spam Here -> postmaster@sco.com