I have been (hours) trouble with associations in Rails. I found a lot of similar problems, but I couldn't apply for my case:
City's class:
class City < ApplicationRecord
has_many :users
end
User's class:
class User < ApplicationRecord
belongs_to :city
validates :name, presence: true, length: { maximum: 80 }
validates :city_id, presence: true
end
Users Controller:
def create
Rails.logger.debug user_params.inspect
@user = User.new(user_params)
if @user.save!
flash[:success] = "Works!"
redirect_to '/index'
else
render 'new'
end
end
def user_params
params.require(:user).permit(:name, :citys_id)
end
Users View:
<%= form_for(:user, url: '/user/new') do |f| %>
<%= render 'shared/error_messages' %>
<%= f.label :name %>
<%= f.text_field :name %>
<%= f.label :citys_id, "City" %>
<select name="city">
<% @city.all.each do |t| %>
<option value="<%= t.id %>"><%= t.city %></option>
<% end %>
</select>
end
Migrate:
class CreateUser < ActiveRecord::Migration[5.0]
def change
create_table :user do |t|
t.string :name, limit: 80, null: false
t.belongs_to :citys, null: false
t.timestamps
end
end
Message from console and browser:
ActiveRecord::RecordInvalid (Validation failed: City must exist):
Well, the problem is, the attributes from User's model that aren't FK they are accept by User.save method, and the FK attributes like citys_id are not. Then it gives me error message in browser saying that "Validation failed City must exist".
Thanks
Try the following:
belongs_to :city, optional: true
According to the new docs:
4.1.2.11 :optional
If you set the :optional option to true, then the presence of the associated object won't be validated. By default, this option is set to false.