Pushing to an Array in Ruby on Rails

Question

I am trying to create a string array inside my model, where I can push new strings (IDs) into the string array - but it's not pushing the correct values.

Here is how the model looks:

class CreateCompanies < ActiveRecord::Migration
  def change
  create_table :companies do |t|

  t.string :name
  t.string :email
  t.string :users, array: true, default: []
  t.timestamps null: false
  end
 end
end

And here is how I'm adding the new values to the array in the Controller:

c = Company.new
c.users << @user.id
c.save

A value does indeed get added to the array, but it's not the ID but just some random value like this:

users: "--- []\n\u{478A6}"

Been stuck at this for a couple of days now - does anyone know what I'm missing?

UPDATE: Added the code where I create a new Company

 def create
@user = User.new(user_params)
if @user.save

  @user.id = SecureRandom.random_number(999999)
  session[:user_id] = @user.id

  c = Company.new
  c.id = SecureRandom.random_number(999999)
  c.name = @user.company_name
  c.email = "email goes here"
  c.users << @user.id
  c.save

  @user.company_id = c.id
  @user.save

  redirect_to '/dashboard'
else
  redirect_to '/'
end
end

Almaron · Accepted Answer · 2016-04-13 18:42:53Z

4

If you're trying to build a one-to-many relationship, what you should do is add a company_id field to the users table, add belongs_to :company to your app/models/user.rb and add has_many :users to your app/models/company.rb.

Then you'd be able to access the users just like you need.

UPDATE

If you want to create a company with the user you can just go like this.

@user.company = Company.create name: 'Some name'

Or even better to avoid duplication.

@user.company = Company.find_or_create_by name: 'Some name'

edited Apr 13, 2016 at 18:42

answered Apr 13, 2016 at 18:33

Almaron

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6 Comments

Dark Knight Over a year ago

I see! So is it enough to simply add a company_id column to the Users table? And how would I be able to later get all the users who belong to a Company?

Almaron Over a year ago

You need to fill all the 3 steps I described. Then you'll be able to call company.users and ActiveRecord will do a query and return an ActiveRecord::Relation object wich acts mostly like an array of users.

Dark Knight Over a year ago

Aha! Currently I'm creating a new Company in the User class, when a new User is created. (with the code above) How would I then link them?

Dark Knight Over a year ago

Thank you! Please see the code in my updated question - could I then set the parameters of the company (such as ID)?

Almaron Over a year ago

yes, you can just set the company_id (and you don't need to call c.users << @user.id), although I really don't understand why would you use SecureRandom to generate primary keys. and also you might use if @user.valid? instead of if @user.save to avoid saving the same object twice and possibly messing up the database.

|

RoyX · Accepted Answer · 2016-04-13 18:25:13Z

0

I wonder if here you want to build many to many relationship, the best way to do this is using a many to many table instead of store all ids as an array string in databases;

If you do want to store like this, the best way should be form a string instead of put array directly. For this things like array.join() would be very helpful for you.

If you still insist your way, maybe you should try array.push() instead of <<

answered Apr 13, 2016 at 18:25

RoyX

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4 Comments

Dark Knight Over a year ago

The current relationship is a one-to-many; A User can only have one company, but a company can have many Users. When I try using .push() I get an No Method error. Hmm, so I could eg. retrieve the string object from the model, then join it with the latest ID and update it?

RoyX Over a year ago

If it is one to many there is no need to put columns in Company table. the normal way to do this is put a column named company_id in User table.

Dark Knight Over a year ago

Aha! I'm pretty new to this. In the User class; belongs_to :company - and in the Company class; has_many :users. I already have a column called t.string :company_name in the User model, how can I link these together?

RoyX Over a year ago

It will automatically create relationship for you, no need to modify the database by yourself. You can read more about this by guides.rubyonrails.org/active_record_basics.html .

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