HI,
i use models User and Groups connected with many to many association, so
i have users table, groups and groups_users.
lets say i create one user and one group. next i add a group to user. so
now my table groups_users has one entry i.e.
group_id | user_id
_________|________
1 | 1
ok, when i delete both my group and user, above entry is not deleted,
thus leaving alone without any reason.. its just an orphan record, which
is useless.
is there any parameter in rails that removes such records ?
i dont want to have too many useless records at all.
btw. its not :dependant => :destroy parameter, this applies only to
has_many association...
regards.
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Piotr Nowak wrote:> group_id | user_id > _________|________ > 1 | 1...> btw. its not :dependant => :destroy parameter, this applies only to > has_many association...I know, that it is not directly an answer to your current problem. But perhaps you should change your HABTM to a "has_many :through" relationship Like this: 1) Change above table from "users_groups" to "memberships" and add an auto-incremented id field (of course as primary key) 2) Create a new model Membership with these declarations: belongs_to :user belongs_to :group 3) in your Group model, replace the HABTM declaration with this: has_many :memberships, :dependent => :destroy has_many :users, :through => :membership 4) ditto in the User model: has_many :memberships, :dependent => :destroy has_many :groups, :through => :membership You ought to be able to do this on your existing database and application without changing any other program lines. The access to the associated data are the same. And the :dependant declaration will take care of future orphans. Hope this helps. - Carsten -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Carsten Gehling pisze:> Piotr Nowak wrote: > >> group_id | user_id >> _________|________ >> 1 | 1 > ... >> btw. its not :dependant => :destroy parameter, this applies only to >> has_many association... > > I know, that it is not directly an answer to your current problem. But > perhaps you should change your HABTM to a "has_many :through" > relationship > > Like this: > > 1) Change above table from "users_groups" to "memberships" and add an > auto-incremented id field (of course as primary key) > > > 2) Create a new model Membership with these declarations: > > belongs_to :user > belongs_to :group > > > 3) in your Group model, replace the HABTM declaration with this: > > has_many :memberships, :dependent => :destroy > has_many :users, :through => :membership > > 4) ditto in the User model: > > has_many :memberships, :dependent => :destroy > has_many :groups, :through => :membership > > > You ought to be able to do this on your existing database and > application without changing any other program lines. The access to the > associated data are the same. And the :dependant declaration will take > care of future orphans. > > Hope this helps. > > - Carstenquite interesting, ill see if that works for me. btw. i wonder why something simple isnt done with regular habtm relationship.. anyway, thanks a lot Carsten :) have a nice day (evening) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Piotr Nowak wrote:> btw. i wonder why something simple isnt done with regular habtm > relationship..I can''t remember when the :dependent keyword was added to ActiveRecord, but I know, that ever since Rails 1.2, "has_many :trough" has been favored by the Rails core team over HABTM. BTW: "has_many :through" has another advantage over HABTM: In your "memberships" table, you are allowed to add attributes e.g. like this memberships --------------- id (int) user_id (int) group_id (int) valid_from (datetime) valid_to (datetime) and access these from your model code.> anyway, thanks a lot Carsten :) > have a nice day (evening)You are very welcome, I am (unfortunately) not often on the Ruby-forum, but it gives me pleasure when I''m able to help others in need. :-) You have a nice evening too. - Carsten -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Carsten Gehling pisze:> Piotr Nowak wrote: > >> btw. i wonder why something simple isnt done with regular habtm >> relationship.. > > I can''t remember when the :dependent keyword was added to ActiveRecord, > but I know, that ever since Rails 1.2, "has_many :trough" has been > favored by the Rails core team over HABTM. > > BTW: "has_many :through" has another advantage over HABTM: In your > "memberships" table, you are allowed to add attributes e.g. like this > > memberships > --------------- > id (int) > user_id (int) > group_id (int) > valid_from (datetime) > valid_to (datetime) > > and access these from your model code. > >> anyway, thanks a lot Carsten :) >> have a nice day (evening) > > You are very welcome, I am (unfortunately) not often on the Ruby-forum, > but it gives me pleasure when I''m able to help others in need. :-) > > You have a nice evening too. > > - Carstenok ive done this, but when i do usr = User.find(:first) usr.groups i get error: ActiveRecord::HasManyThroughAssociationNotFoundError: Could not find the associa tion :membership in model User my models and tables are as follows class User < ActiveRecord::Base has_many :memberships, :dependent => :destroy has_many :groups, :through => :membership end class Membership < ActiveRecord::Base belongs_to :user belongs_to :group end class Group < ActiveRecord::Base has_many :memberships, :dependent => :destroy has_many :users, :through => :membership end excerpt form my schema.rb: create_table "memberships", :force => true do |t| t.column "group_id", :integer t.column "user_id", :integer end any ideas ? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
ok, figured it out :)
class User < ActiveRecord::Base
has_many :memberships, :dependent => :destroy
has_many :groups, :through => :membership
end
class Group < ActiveRecord::Base
has_many :memberships, :dependent => :destroy
has_many :users, :through => :membership
end
should be:
class User < ActiveRecord::Base
has_many :memberships, :dependent => :destroy
has_many :groups, :through => :memberships
end
class Group < ActiveRecord::Base
has_many :memberships, :dependent => :destroy
has_many :users, :through => :memberships
end
In overall the through attribute value should be pluralized :)
big thank you
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Piotr Nowak pisze:> ok, figured it out :) > > class User < ActiveRecord::Base > has_many :memberships, :dependent => :destroy > has_many :groups, :through => :membership > end > > class Group < ActiveRecord::Base > has_many :memberships, :dependent => :destroy > has_many :users, :through => :membership > end > > > should be: > > class User < ActiveRecord::Base > has_many :memberships, :dependent => :destroy > has_many :groups, :through => :memberships > end > > class Group < ActiveRecord::Base > has_many :memberships, :dependent => :destroy > has_many :users, :through => :memberships > end > > > In overall the through attribute value should be pluralized :) > > big thank you > > > > >well, although it works, it doesnt resolve my problem when i delete user or group, the membership item (containng both those user and group) is not deleted... wonder why.. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Piotr Nowak pisze:> Piotr Nowak pisze: >> ok, figured it out :) >> >> class User < ActiveRecord::Base >> has_many :memberships, :dependent => :destroy >> has_many :groups, :through => :membership >> end >> >> class Group < ActiveRecord::Base >> has_many :memberships, :dependent => :destroy >> has_many :users, :through => :membership >> end >> >> >> should be: >> >> class User < ActiveRecord::Base >> has_many :memberships, :dependent => :destroy >> has_many :groups, :through => :memberships >> end >> >> class Group < ActiveRecord::Base >> has_many :memberships, :dependent => :destroy >> has_many :users, :through => :memberships >> end >> >> >> In overall the through attribute value should be pluralized :) >> >> big thank you >> >> > > well, although it works, it doesnt resolve my problem > when i delete user or group, the membership item (containng both those > user and group) is not deleted... > > wonder why.. > > > > >just noticed that it works only when i do destroy method on my user or group instead of delete... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Piotr Nowak wrote:> should be: > > class User < ActiveRecord::Base > has_many :memberships, :dependent => :destroy > has_many :groups, :through => :membershipsSorry, a typo from me... Sometimes i just hate David for doing the pluralization thing... ;-) David hvis du læser dette, så: Puha! Slemme dreng! :-) (just a little rambling in Danish - I''m from Denmark as well) - Carsten -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Piotr Nowak wrote:> just noticed that it works only when i do destroy method on my user or > group instead of delete...From the API description of ActiveRecord: -------------------------------------------------- delete(id) Deletes the record with the given id without instantiating an object first. If an array of ids is provided, all of them are deleted. destroy(id) Destroys the record with the given id by instantiating the object and calling destroy (all the callbacks are the triggered). If an array of ids is provided, all of them are destroyed. -------------------------------------------------- The essential here is that delete(id) "deletes without instantiating an object first". Which really boils down to a SQL like "delete from users where id = NN limit 1" delete() does not instantiate the object, therefore it knows nothing of any associations/relationships. Always use destroy() if possible. - Carsten -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
> > Always use destroy() if possible. > > - Carsteni will, rails rocks ! i ve just switched from java/.net to rails and im so excited so far :) greets. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Piotr Nowak wrote:> i will, rails rocks ! > > i ve just switched from java/.net to rails and im so excited so far :)Have you seen these? http://www.railsenvy.com/tags/Commercials Start with the ones in the bottom - they are fun and - IMHO quite accurate :-) Been at a few of the langauges/frameworks myself earlier. Now I only do PHP and Rails - and PHP only because I have so many existing customers/solutions that I would hate to rewrite. But you''ve made a good choice - you won''t regret it! - Carsten -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Carsten Gehling pisze:> Piotr Nowak wrote: > >> i will, rails rocks ! >> >> i ve just switched from java/.net to rails and im so excited so far :) > > Have you seen these? > > http://www.railsenvy.com/tags/Commercials > > Start with the ones in the bottom - they are fun and - IMHO quite > accurate :-) > > Been at a few of the langauges/frameworks myself earlier. Now I only do > PHP and Rails - and PHP only because I have so many existing > customers/solutions that I would hate to rewrite. > > But you''ve made a good choice - you won''t regret it! > > - Carstenyes, ive seen them all, pretty funny, especially rails vs .net #2 :) starting 2 projects now in rails, im quite excited :) greets. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---