Rails - Mar 2006 - Through relationship

I am working on streamlining one of my apps, and trying to wrap my  
hands around through, polymorphic, and with_scope. All of these i  
know i need for what i want to do, based on the little documentation  
I have found. With this in mid I have tried to implement a simple  
through in the app to try and get my head around it. This is what I  
have:

class Product < ActiveRecord::Base
   has_many :subscriptions
   has_many :accounts, :through => :subscriptions
end

class Subscription < ActiveRecord::Base
   belongs_to :product
   belongs_to :account
end

class Account < ActiveRecord::Base
   has_many :subscriptions
   has_many :products, :through => :subscriptions
end

in my controller i have the following code:

@account = Account.find(@user.account_id)
@products = @account.products

but i recieve the following error:

You have a nil object when you didn''t expect it!
The error occured while evaluating nil.options
RAILS_ROOT: /Users/flip/Documents/workspace/SolidSuite/public/../ 
config/..

Application Trace | Framework Trace | Full Trace
#{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
associations/has_many_through_association.rb:66:in  
`construct_conditions''
#{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
associations/has_many_through_association.rb:7:in `initialize''
#{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
associations.rb:695:in `new''
#{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
associations.rb:695:in `products''
#{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
associations.rb:690:in `products''
#{RAILS_ROOT}/app/controllers/account_controller.rb:65:in `products''


I updated my edge rails (doing it manual for many reasons). I am on  
changeset: 3747 as far as I can tell however when i followed the  
instructions on the wiki I cound not find a bin directory as the last  
few steps mention in regards to replacing some files with newer  
versions based on certain files on edge are not compatable with 1.0  
files.

My db is mysql 5.0.18 and i have all the appropriate keys set. If i  
remove the call to the through as well as the specific through call  
and go back to the way I was doing it things work fine. Again I am  
trying to do things very simple and than once I get the feel for it i  
was going to optimize because I know what I am doing is not optimize.

Any help would be much appreciated.

As a side note another question is that I have tried this on a HABTM  
relationship and get similar errors.

Thanks again

Andrew

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Andrew,

I''m getting this same error and am wondering what I''m doing
wrong
also.  Not sure if it''s me or the code :)  If anyone else knows  
what''s going on, please do pipe up.

Duane Johnson
(canadaduane)
http://blog.inquirylabs.com/

On Mar 2, 2006, at 6:37 PM, Andrew Filipowski wrote:
> I am working on streamlining one of my apps, and trying to wrap my  
> hands around through, polymorphic, and with_scope. All of these i  
> know i need for what i want to do, based on the little  
> documentation I have found. With this in mid I have tried to  
> implement a simple through in the app to try and get my head around  
> it. This is what I have:
>
> class Product < ActiveRecord::Base
>   has_many :subscriptions
>   has_many :accounts, :through => :subscriptions
> end
>
> class Subscription < ActiveRecord::Base
>   belongs_to :product
>   belongs_to :account
> end
>
> class Account < ActiveRecord::Base
>   has_many :subscriptions
>   has_many :products, :through => :subscriptions
> end
>
> in my controller i have the following code:
>
> @account = Account.find(@user.account_id)
> @products = @account.products
>
> but i recieve the following error:
>
> You have a nil object when you didn''t expect it!
> The error occured while evaluating nil.options
> RAILS_ROOT: /Users/flip/Documents/workspace/SolidSuite/public/../ 
> config/..
>
> Application Trace | Framework Trace | Full Trace
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
> associations/has_many_through_association.rb:66:in  
> `construct_conditions''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
> associations/has_many_through_association.rb:7:in `initialize''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
> associations.rb:695:in `new''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
> associations.rb:695:in `products''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/ 
> associations.rb:690:in `products''
> #{RAILS_ROOT}/app/controllers/account_controller.rb:65:in
`products''
>
>
> I updated my edge rails (doing it manual for many reasons). I am on  
> changeset: 3747 as far as I can tell however when i followed the  
> instructions on the wiki I cound not find a bin directory as the  
> last few steps mention in regards to replacing some files with  
> newer versions based on certain files on edge are not compatable  
> with 1.0 files.
>
> My db is mysql 5.0.18 and i have all the appropriate keys set. If i  
> remove the call to the through as well as the specific through call  
> and go back to the way I was doing it things work fine. Again I am  
> trying to do things very simple and than once I get the feel for it  
> i was going to optimize because I know what I am doing is not  
> optimize.
>
> Any help would be much appreciated.
>
> As a side note another question is that I have tried this on a  
> HABTM relationship and get similar errors.
>
> Thanks again
>
> Andrew
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
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:through associations are working fine for me on edge. How are you 
setting up your objects? Your model classes look right, but do you have 
the objects hooked together properly? Like, did you create the 
subscriptions?

I''ve been blogging a series on how to use :through associations in 1.1.
Check it out and see if it helps. If not let me know and maybe I can 
help.

http://blog.hasmanythrough.com/articles/2006/02/28/association-goodness

--josh
blog.hasmanythrough.com

Andrew Filipowski wrote:
> I am working on streamlining one of my apps, and trying to wrap my
> hands around through, polymorphic, and with_scope. All of these i
> know i need for what i want to do, based on the little documentation
> I have found. With this in mid I have tried to implement a simple
> through in the app to try and get my head around it. This is what I
> have:
> 
> class Product < ActiveRecord::Base
>    has_many :subscriptions
>    has_many :accounts, :through => :subscriptions
> end
> 
> class Subscription < ActiveRecord::Base
>    belongs_to :product
>    belongs_to :account
> end
> 
> class Account < ActiveRecord::Base
>    has_many :subscriptions
>    has_many :products, :through => :subscriptions
> end
> 
> in my controller i have the following code:
> 
> @account = Account.find(@user.account_id)
> @products = @account.products
> 
> but i recieve the following error:
> 
> You have a nil object when you didn''t expect it!
> The error occured while evaluating nil.options
> RAILS_ROOT: /Users/flip/Documents/workspace/SolidSuite/public/../
> config/..
> 
> Application Trace | Framework Trace | Full Trace
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/
> associations/has_many_through_association.rb:66:in
> `construct_conditions''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/
> associations/has_many_through_association.rb:7:in `initialize''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/
> associations.rb:695:in `new''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/
> associations.rb:695:in `products''
> #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/
> associations.rb:690:in `products''
> #{RAILS_ROOT}/app/controllers/account_controller.rb:65:in
`products''
> 
> 
> I updated my edge rails (doing it manual for many reasons). I am on
> changeset: 3747 as far as I can tell however when i followed the
> instructions on the wiki I cound not find a bin directory as the last
> few steps mention in regards to replacing some files with newer
> versions based on certain files on edge are not compatable with 1.0
> files.
> 
> My db is mysql 5.0.18 and i have all the appropriate keys set. If i
> remove the call to the through as well as the specific through call
> and go back to the way I was doing it things work fine. Again I am
> trying to do things very simple and than once I get the feel for it i
> was going to optimize because I know what I am doing is not optimize.
> 
> Any help would be much appreciated.
> 
> As a side note another question is that I have tried this on a HABTM
> relationship and get similar errors.
> 
> Thanks again
> 
> Andrew

-- 
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