I have the following many-to-many relationships defined in my model code
to model a many to many relationship between Media and PriceCode with
Price being the association table:
class Media < ActiveRecord::Base
has_many :prices
has_many :price_codes, :through => :prices
end
class Price < ActiveRecord::Base
belongs_to :media
belongs_to :price_code
end
class PriceCode < ActiveRecord::Base
has_many :prices
has_many :medias, :through => :prices
end
Based this exmaple off a recipr in the Rails Recipies Cookbook.
When I manually add data to the underlying tables, I can correctly
display the data through by navigating through the object model.
What I''m having trouble figuring out is how to delete Price records
form
the association table.
Within one of my forms I have the following:
<%= link_to ''Destroy'', { :action =>
''destroy_price'', :id => @media.id,
:price_code_id =>price_code.id }, :confirm => ''Are you
sure?'', :post =>
true %>
Add here is the destroy_price action in the controller:
def destroy_price
Media.find(params[:id]).prices.find(params[:price_code_id]).destroy
redirect_to :action => ''show'', :id => params[:id]
end
When I call the action the following error is returned:
ActiveRecord::StatementInvalid in MediaController#destroy_price
Mysql::Error: #42S22Unknown column ''prices.id'' in
''where clause'': SELECT
* FROM prices WHERE (prices.id = ''1'' AND (prices.media_id =
82)) LIMIT
1
For this example I''m trying to delete the prices record with media_id
of
82 and price_code_id of 1. For some reason the sql that is getting
generated by ActiveRecord is using prices.id = ''1'' rather than
prices.price_code_id = 1.
Not really sure what to do next to attempt to get this to work...
Any ideas would be greatly appreciated.
JD
--
Posted via http://www.ruby-forum.com/.
jim dandy wrote:> I have the following many-to-many relationships defined in my model code > to model a many to many relationship between Media and PriceCode with > Price being the association table: > > class Media < ActiveRecord::Base > has_many :prices > has_many :price_codes, :through => :prices > end > > class Price < ActiveRecord::Base > belongs_to :media > belongs_to :price_code > end > > class PriceCode < ActiveRecord::Base > has_many :prices > has_many :medias, :through => :prices > end > > Based this exmaple off a recipr in the Rails Recipies Cookbook. > > When I manually add data to the underlying tables, I can correctly > display the data through by navigating through the object model. > > What I''m having trouble figuring out is how to delete Price records form > the association table. > > Within one of my forms I have the following: > > <%= link_to ''Destroy'', { :action => ''destroy_price'', :id => @media.id, > :price_code_id =>price_code.id }, :confirm => ''Are you sure?'', :post => > true %> > > Add here is the destroy_price action in the controller: > > def destroy_price > Media.find(params[:id]).prices.find(params[:price_code_id]).destroy > redirect_to :action => ''show'', :id => params[:id] > end > > When I call the action the following error is returned: > > ActiveRecord::StatementInvalid in MediaController#destroy_price > > Mysql::Error: #42S22Unknown column ''prices.id'' in ''where clause'': SELECT > * FROM prices WHERE (prices.id = ''1'' AND (prices.media_id = 82)) LIMIT > 1 > > For this example I''m trying to delete the prices record with media_id of > 82 and price_code_id of 1. For some reason the sql that is getting > generated by ActiveRecord is using prices.id = ''1'' rather than > prices.price_code_id = 1. > > Not really sure what to do next to attempt to get this to work... > > Any ideas would be greatly appreciated. > > JD>From an iRB session I can find the Prices record, but trying to destroyit produces this error. I don''t know why it''s looking for an id since there is no id in the prices table:>> Price.find_by_media_id_and_price_code_id(82,2)=> #<Price:0x388a22c @attributes={"media_id"=>"82", "updated_at"=>"2006-08-08 18:04:35", "price_code_id"=>"2", "created_at"=>"2006-08-08 18:04:35"}>>> Price.find_by_media_id_and_price_code_id(82,2).destroyActiveRecord::StatementInvalid: Mysql::Error: Unknown column ''id'' in ''where clause'': DELETE FROM prices WHERE id = NULL -- Posted via http://www.ruby-forum.com/.
jim dandy wrote:> From an iRB session I can find the Prices record, but trying to destroy > it produces this error. I don''t know why it''s looking for an id since > there is no id in the prices table: > >>> Price.find_by_media_id_and_price_code_id(82,2) > => #<Price:0x388a22c @attributes={"media_id"=>"82", > "updated_at"=>"2006-08-08 18:04:35", "price_code_id"=>"2", > "created_at"=>"2006-08-08 18:04:35"}> > >>> Price.find_by_media_id_and_price_code_id(82,2).destroy > ActiveRecord::StatementInvalid: Mysql::Error: Unknown column ''id'' in > ''where clause'': DELETE FROM prices WHERE id = NULLYou NEED an id in the join model. has_many :through won''t work without it. -- Josh Susser http://blog.hasmanythrough.com/ -- Posted via http://www.ruby-forum.com/.