Creating objects with associations in Rails

Question

In my Rails app I have Clients and Users. And Users can have many Clients.

The models are setup as so:

class Client < ApplicationRecord
  has_many :client_users, dependent: :destroy
  has_many :users, through: :client_users
end

class User < ApplicationRecord
  has_many :client_users, dependent: :destroy
  has_many :clients, through: :client_users
end

class ClientUser < ApplicationRecord
  belongs_to :user
  belongs_to :client
end

So if I wanted to create a new client that had the first two users associated with it how would I do it?

e.g.

Client.create!(name: 'Client1', client_users: [User.first, User.second])

Trying that gives me the error:

ActiveRecord::AssociationTypeMismatch: ClientUser(#70142396623360) expected, got #<User id: 1,...

I also want to do this for an RSpec test. e.g.

user1 = create(:user)
user2 = create(:user)

client1 = create(:client, client_users: [user1, user2])

How do I create a client with associated users for in both the Rails console and in an RSpec test?

Try This User.create(name: 'oneuser') User.create(name: 'twouser') @client = Client.create(name: 'Client1') @client.users << User.first @client.users << User.second — Vaibhav Dhoke
– Vaibhav Dhoke, Commented Sep 27, 2017 at 9:51
@VaibhavDhoke So the client has to exist first? I can't create and associate at the same time? — Cameron
– Cameron, Commented Sep 27, 2017 at 9:54
This is one way of doing it, maybe that also could be done, but I am not aware of it. still. Please refer this link for more info. — Vaibhav Dhoke
– Vaibhav Dhoke, Commented Sep 27, 2017 at 9:56

marmeladze · Accepted Answer · 2017-09-27 10:38:08Z

2

If you do not want to accept_nested_attributes for anything, as documented here you can also pass block to create.

Client.create!(name: 'Client1') do |client1| 
  client1.users << [User.find(1), User.find(2), User.find(3)]     
end

answered Sep 27, 2017 at 10:38

marmeladze

6,5863 gold badges28 silver badges49 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

krishna raikar · Accepted Answer · 2017-09-27 10:48:31Z

1

Try this. It should work

Client.create!(name: 'Client1').client_users.new([{user_id: User.first},{user_id: User.second}])

answered Sep 27, 2017 at 10:48

krishna raikar

2,66511 silver badges23 bronze badges

1 Comment

krishna raikar Over a year ago

@Cameron Try above solution

Hirurg103 · Accepted Answer · 2017-09-27 12:33:00Z

You can do this with the following code:

user1 = create(:user)
user2 = create(:user)

client1 = create(:client, users: [user1, user2])

See ClassMethods/has_many for the documentation

collection=objects

Replaces the collections content by deleting and adding objects as appropriate. If the :through option is true callbacks in the join models are triggered except destroy callbacks, since deletion is direct.

If you are using factory_girl you can add trait :with_users like this:

FactoryGirl.define do
  factory :client do

    trait :with_two_users do
      after(:create) do |client|
        client.users = create_list :user, 2
      end
    end

  end
end

Now you can create a client with users in test like this:

client = create :client, :with_two_users

Anand · Accepted Answer · 2017-09-27 09:59:12Z

0

accepts_nested_attributes_for :users

and do as so:

Client.create!(name: 'Client1', users_attributes: { ........ })

hope this would work for you.

answered Sep 27, 2017 at 9:59

Anand

6,5414 gold badges14 silver badges27 bronze badges

Comments

Nimish Gupta · Accepted Answer · 2017-09-27 11:49:18Z

0

You can make use of after_create callback

class Client < ApplicationRecord
  has_many :client_users, dependent: :destroy
  has_many :users, through: :client_users

  after_create :add_users

  private def add_users
    sef.users << [User.first, User.second]
  end
end

Alternatively, A simpler approach would be

Client.create!(name: 'Client1', user_ids: [User.first.id, User.second.id])

answered Sep 27, 2017 at 11:49

Nimish Gupta

3,1851 gold badge17 silver badges21 bronze badges

Comments

coreyward · Accepted Answer · 2017-09-28 18:56:16Z

The reason you're getting a mismatch is because you're specifying the client_users association that expects ClientUser instances, but you're passing in User instances:

# this won't work
Client.create!(client_users: [User.first, User.second])

Instead, since you already specified a users association, you can do this:

Client.create!(users: [User.first, User.second])

There's a simpler way to handle this, though: ditch the join model and use a has_and_belongs_to_many relationship. You still need a clients_users join table in the database, but you don't need a ClientUser model. Rails will handle this automatically under the covers.

class Client < ApplicationRecord
  has_and_belongs_to_many :users
end

class User
  has_and_belongs_to_many :clients
end

# Any of these work:
client = Client.new(name: "Kung Fu")
user = client.users.new(name: "Panda")
client.users << User.new(name: "Nemo")
client.save # => this will create two users and a client, and add two records to the `clients_users` join table

Collectives™ on Stack Overflow

Creating objects with associations in Rails

6 Answers 6

Comments

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

6 Answers 6

Comments

1 Comment

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related