CODEWITHSUNDEEP
ruby-on-railsrubyactiverecordmany-to-many
JazzJackrabbit
JazzJackrabbit

Reputation: 515

Update many-to-many relation with Rails

I'm curious if it's possible to update a bunch of records in a join table that's not registered in an ActiveRecord as a model.

I have 2 classes, lets say A and B, joined by table AsBs. 

class A < ActiveRecord::Base
  attr_accessible :A_name, :B_ids
  has_and_belongs_to_many :Bs, join_table: :AsBs
end

class B < ActiveRecord::Base
  attr_accessible :B_name, :A_ids
  has_and_belongs_to_many :As, join_table: :AsBs
end

class CreateAsBs < ActiveRecord::Migration
  def up
    create_table :AsBs, id: :false do |t|
      t.integer :A_id
      t.integer :B_id
    end
   end
end

I also have a form with checkboxes for B records, which returns a params hash like the one below

params[:my_form]
>> { "B_name_1" => "1", "B_name_2" => "0", "B_name_3" => "0"} 

#What means the user has chosen only first checkbox

What I need is to update the A-B relations, using that params hash or other custom hash based on it's content. Eventually I need this simple example to create a 

A_id | B_id
  1  |  1

record in my :AsBs table and remove 1-2 and 1-3 records, if any.

I obviously can create an AsBs model and edit it manually, but I'd expect using something like update / update_all / update_attributes for @a.Bs or @a.B_ids

Any advice?

Upvotes: 2

Views: 2092

Answers (1)

Llu&#237;s
Llu&#237;s

Reputation: 1317

If I understand correctly you should be able to do

@b.as = [@a]
@b.save

Upvotes: 4

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