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Create Nested Form in Rails 3.1



While we creating some forms, also need to create some additional forms. In rails can easily create those type of form using gem “nested_form”. It can  manage multiple nested models in a single form. To know more

can see how it works

i have two model name Project,task. Project has many task. i want to create multiple task when create a project.

include gem in Gemfile

gem "nested_form", :git => ''

then run command in  project directory

$ bundle install

This gem add new  nested model by using JavaScript. it automatically create JavaScript file.To create JavaScript run this command

$ rails g nested_form:install

now one file created in public/javascripts/nested_form.js

copy the nested_form.js  to app/assets/javascripts/

if your server is running restart to load new installation.

set controller and model like


class ProjectsController < ApplicationController
def index

def new

def create[:project])
flash[:notice] = "Successfully Created project."
redirect_to projects_path

def edit

def update
flash[:notice] = "Record Successfully updated"
redirect_to projects_path

def destroy
redirect_to projects_path


in project.rb

class Project < ActiveRecord::Base
has_many :tasks, :dependent => :destroy
attr_accessible :tasks_attributes,:name, :description
accepts_nested_attributes_for :tasks, :allow_destroy => true

validates :name, :presence => true

in task.rb

class Task < ActiveRecord::Base
belongs_to :project

in my views/projects/_form.html.erb

<%= nested_form_for @project do |f| %>

<%= f.label :name %>
<%= f.text_field(:name) %><br />
<%= f.label :description %>
<%= f.text_field(:description) %><br />
<h3> Tasks</h3>
<%= f.fields_for :tasks do |task| %>
<%= task.label :name %><br />
<%= task.text_field :name %><br />
<%= task.link_to_remove "Remove this task" %>
<% end %>
<p><%= f.link_to_add "Add a task", :tasks %></p>
<%= f.submit %>
<% end %>

f.fields_for :tasks render the partial file “task_fields” create  partial file name as _task_fields.html.erb in views/projects/

and include the nested fields.

while click “link_to_add’, “link_to_remove” it calls the addField removeField in nested_forms.js file.

Nested form fields are added via javascript.



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