CODEWITHSUNDEEP
ruby-on-rails
Christian Fazzini
Christian Fazzini

Reputation: 19723

What's the equivalent for update_attributes?

Normally, when I add a new product to an @announcement, I do:

@announcement = Announcement.find(params[:id])
@announcement.products << Product.find_all_by_id(params[:announcement_products])

What's the equivalent of doing @announcement.products << Product.find_all_by_id(params[:announcement_products]) for update_attributes()?

As a reference, my model definition looks like:

MODEL

class Product < ActiveRecord::Base
  has_many :announcement_products
  has_many :announcements, :through => :announcement_products

  accepts_nested_attributes_for :announcements#, :reject_if => lambda { |a| a[:content].blank? }, :allow_destroy => true
end

class Announcement < ActiveRecord::Base
  has_many :announcement_products
  has_many :products, :through => :announcement_products

  accepts_nested_attributes_for :products#, :reject_if => lambda { |a| a[:content].blank? }, :allow_destroy => true
end

class AnnouncementProduct < ActiveRecord::Base
  belongs_to :announcement
  belongs_to :product
end

Upvotes: 2

Views: 1082

Answers (2)

Preston Marshall
Preston Marshall

Reputation: 1195

Just set :product_ids in the params for attachment. So 

{:announcement=>{:name=>"foo222", :description=>"bar", :product_ids => [8, 9]}}

is what you are looking for. This can be achieved with checkboxes or anything else that sends an "array" in the http request.

Also, if you're using attr_accessible, don't forget to add the product_ids attribute to the list, just remember to look out for mass assignment if you need to.

Upvotes: 2

Max Williams
Max Williams

Reputation: 32955

Look up the association methods that has_many gives you. Among them are "association_ids=", which expects an array of ids. This works well with update_attributes, because if you do this

params = {:product => {:announcement_ids => [1,2,3]}}
@product.update_attributes(params[:product])

that effectively does 

@product.announcement_ids = [1,2,3]

This works well with checkboxes in a form, writing announcement ids to "product[announcement][]" for example.

Upvotes: 2

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