9

I have two models: (Albums and Product)

1) Inside Models

Inside album.rb:

class Album < ActiveRecord::Base
  attr_accessible :name
  has_many :products
end

Inside product.rb:

class Product < ActiveRecord::Base
  attr_accessible :img, :name, :price, :quantity
  belongs_to :album
end

2) Using "rails console", how can I set the associations (so I can use "<%= Product.first.album.name %>")?

e.g.

a = Album.create( :name => "My Album" )
p = Product.create( :name => "Shampoo X" )
# what's next? how can i set the album and the product together?
MrYoshiji
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rosary dextrose
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2 Answers2

12

You can do like this:

a = Album.create( name: "My Album" )

p = Product.create( name: "Shampoo X" )
# OR
p = Product.create( name: "Shampoo X", album_id: a.id )
# OR
p.album = a
# OR
p.album_id = a.id
# OR 
a.products << a
# finish with a save of the object:
p.save

You may have to set the attribute accessible to album_id on the Product model (not sure about that).

Check @bdares' comment also.

MrYoshiji
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    If you add the `_id` to accessible, then you can just stick the id value as you instantiate it: `Product.create(name:'Shampoo',album_id:a.id)` –  Dec 26 '12 at 00:25
  • @bdares To add _id, I just have to use `attr_accessible :img, :name, :price, :quantity, :_id`, right? However, it gives me this error, `ActiveModel::MassAssignmentSecurity::Error: Can't mass-assign protected attributes: album_id` – rosary dextrose Dec 26 '12 at 02:21
  • @MrYoshiji, For `p.album = a`, it temporarily works, but if I reopen the console, the p.album turns into "nil". For `p.album_id = a.id`, it gives this error, `NoMethodError: undefined method 'album_id='`. For `a.products << p`, it gives this error, `RuntimeError: can't modify frozen Hash`. Do I need to regenerate both models? Thank you everyone! – rosary dextrose Dec 26 '12 at 02:33
  • You have to give access to the album_id attribute: `attr_accessible :img, :name, :price, :quantity, :album_id` – MrYoshiji Dec 26 '12 at 03:11
  • Thanks! Apparently, I have to recreate the Product Model to have `album_id:integer`, not just add it in `attr_accessible`. – rosary dextrose Dec 26 '12 at 03:41
  • Yes you have to generate a migration (http://api.rubyonrails.org/classes/ActiveRecord/Migration.html) in order to add the new column `album_id` as integer in the database. – MrYoshiji Dec 26 '12 at 04:16
2

Add the association when you create the Product:

a = Album.create( :name => "My Album" )
p = Product.create( :name => "Shampoo X", :album => a )
Ross Allen
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  • It temporarily works. However, if I reopen the console, the p.album turns into "nil".. – rosary dextrose Dec 26 '12 at 02:18
  • Are you fetching the same `Product` you created the first time? Try the above code, then reopen the console and try `Product.find_by_name('Shampoo X').album`. – Ross Allen Dec 31 '12 at 09:25