CODEWITHSUNDEEP
ruby-on-railsformsmodelpopulate
Aida
Aida

Reputation: 85

How to automatically fill in the form with data from other models in Rails

I'm new to Rails. I'm trying to make an app where students can log in and signup for the exam. I have the following models and controllers which are related to that:

The subject has the following columns:

t.string  "name"  t.integer "ects"
t.integer "year" t.integer "professor_id"

Its relationship with exam: has_one :exam Its relationship with a professor: belongs_to :professor

Professor has the following columns:

t.string  "first_name"
t.string  "last_name"
t.string  "title"

Its relationship with exam: has_many :exams Its relationship with subject: has_many :subjects

Exam has the following columns: 

t.date    "start_date"  
t.string  "department"  
t.integer "professor_id"  
t.integer "subject_id"

Its relationship with subject: belongs_to :subject Its relationship with a professor: belongs_to :professor Its relationship with signup: 

has_many :signups
has_many :signupers, through: :signups, class_name: 'User'

Signup has the following columns: 

t.integer "exam_id"
t.integer "user_id"

Its relationship with the exam: belongs_to :exam Its relationship with user: belongs_to :user

I have already connected everything and made a signup button on the exam show view which is linked to new_signup_path. I want data to appear in the form when the user is redirected to it. I would like for the subject name, professor's name and start date to be shown in the form. So, the user has to click the submit button only.

I have made this form, which works, but it's empty: 

<%= form_for @signup do |f| %>
    <%= f.fields_for :exam do |e| %>   
       <%= e.label :start_date %>
       <%= e.date_field :start_date %> 
    <% end %> 
    <%= f.submit "Submit", class: "btn btn-large btn-primary" %> 
<% end %>

I also want to have professor's name (Professor model) and subject name (Subject model).

this is my signups controller: 

before_action :signed_in_user, only: [:index, :new, :create]

def index
    if current_user.role == 1
        @signups = Signup.all
    else  
        @signups = Signup.where(user_id:current_user.id)
    end
end 

def new
    @signup = Signup.new
end 

def create
    @signup = Signup.new(signup_paramas)
    @signup.user_id = current_user.id
    if @signup.save
        flash[:success] = "You signed up for the exam."
        redirect_to @signups
    else 
        render :new
    end
end
private 
def signup_paramas
    params.require(:signup).permit(:user_id).merge(exam_id: @exam.id)
end

I've been googling this issue for 2 weeks, but I haven't been able to find a solution. I appreciate any kind of help. Thanks in advance :)

Upvotes: 4

Views: 3461

Answers (1)

Slava.K
Slava.K

Reputation: 3080

On signup button add exam_id to redirect url parameters: new_signup_path(exam_id: @exam.id)

Then in the new action of the signups controller you will be able to access exam:

def new
  @signup = Signup.new
  @exam = Exam.find(params[:exam_id])
end

After this you will be able to use @exam in the view to populate form fields:

<%= form_for @signup do |f| %>
  <%= f.fields_for :exam do |e| %>   
    <%= e.label :start_date %>
    <%= e.date_field :start_date, value: @exam.start_date %> 
  <% end %> 
  <%= f.submit "Submit", class: "btn btn-large btn-primary" %> 
<% end %>

You will also be able to access professor and subject through @exam. This is something to give you an idea from where to start from.

Upvotes: 4

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