Updating multiple tables with one form

Hi all,

Here is the setup:

I’m writing an application to model a house. Houses have rooms. I
need the room to have a name, an id, and then one or more lights. Each
light has wattage, hours_per_day, and quantity. I’d also like the room
to have many small_appliances, but I haven’t gotten that far yet.

The best I’ve been able to figure out is to have a separate table for
Lights so that a room can have many lights. My setup is a Houses table
that has_many Rooms. I have a Rooms table that has_many Lights. I
have a page where you can add a Room to a House.

On this page there is a text_field for name, and 3 sets of text_fields
for the lights, since I can’t figure out a way to allow the user to
dynamically add extra lights. The code snippet:


<% # form_for :room, :url => { :action => :add_room, :id => @house }
do |form| %>

<legend>Add a Room</legend>

<div>
  <%= form.label :name, "Name of room: " %>
  <%= form.text_field :name %>
</div>

<p><strong>Lights</strong></p>

<p class="description tier2">Enter lighting information for up to

three different types of lights.

<div id="lights0">
  <%= form.label :number_of_lights, "Number of lights: " %>
  <%= form.text_field :number_of_lights, :size => 2 %><br />
  <%= form.label :wattage, "Wattage of lights: " %>
  <%= form.text_field :wattage, :size => 2 %><br />
  <%= form.label :hours_used_per_day, "Number of hours per day

lights are on: " %>
<%= form.text_field :hours_used_per_day, :size => 2 %>

<div id="lights1">
  <%= form.label :number_of_lights1, "Number of lights: " %>
  <%= form.text_field :number_of_lights1, :size => 2 %><br />
  <%= form.label :wattage1, "Wattage of lights: " %>
  <%= form.text_field :wattage1, :size => 2 %><br />
  <%= form.label :hours_used_per_day1, "Number of hours per day

lights are on: " %>
<%= form.text_field :hours_used_per_day1, :size => 2 %>

<div id="lights2">
  <%= form.label :number_of_lights2, "Number of lights: " %>
  <%= form.text_field :number_of_lights2, :size => 2 %><br />
  <%= form.label :wattage2, "Wattage of lights: " %>
  <%= form.text_field :wattage2, :size => 2 %><br />
  <%= form.label :hours_used_per_day2, "Number of hours per day

lights are on: " %>
<%= form.text_field :hours_used_per_day2, :size => 2 %>

<%= submit_tag "Add room" %>
<% end %>

And here is the code snippet from the controller.


def add_room
@house = House.find(params[:id])
@room = Room.new(params[:room])
@light = Light.new(params[:light])

respond_to do |format|
  if @room.save
    @light.save
    @house.add_room(@room)
    @house.save
    flash[:notice] = "Room \"#{@room.name}\" was successfully

added."
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room, :status
=> :created, :location => @room }
else
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room.errors, :status
=> :unprocessable_entity }
end
end
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before adding a room”
redirect_to :action => ‘index’
end


My problem is that I can’t get this form to save the room and lights
(and later small_appliances). After reading various sources I was
trying to use <% form_tag({:controller => “calculator”, :action =>
“add_room”} ) %> instead of form_for, but I’m not sure how to access
the params correctly. How can I save to both tables?

Thanks in advance,
Ryan

Hi Ryan,

Try this out
<% form_for :room, :url => { :action => :add_room, :id => @house } do
|form| %>
<%= form.label :name, "Name of room: " %>
<%= form.text_field :name %>
/* Differentiate lights parameter using following way */

  <%= text_field :light,:number_of_lights, :size => 2 %><br />
  <%= text_field :light, :wattage, :size => 2 %><br />

<% end %>

And in your controller do the following

def add_room
@house = House.find(params[:id])
@room = Room.new(params[:room])
@light = Light.new(params[:light])

respond_to do |format|
  ## Save all the parameter only if they are valid, if any of your 

object is not pass validation then no one of the below get saved.
if @room.valid? && @light.valid? && @house.valid? && @room.save
&& @light.save && @house.add_room(@room) && @house.save
flash[:notice] = “Room “#{@room.name}” was successfully
added.”
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room, :status
=> :created, :location => @room }
else
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room.errors, :status
=> :unprocessable_entity }
end
end
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before adding a room”
redirect_to :action => ‘index’
end

try it & let me know if u face any problem

Thanks,

Salil G.

This seems to be working nicely. However, the room_id is not being
saved into the Lights table. What am I missing.

Also, how to I get each set of text boxes to save to a new row in the
Lights table?

  • Ryan

On Oct 6, 2:28 am, Salil G. [email protected]

If I’m not wrong, this is what you need:
http://media.pragprog.com/titles/fr_arr/multiple_models_one_form.pdf

Here is an example of some complex forms by ryanb:

http://github.com/ryanb/complex-form-examples

You can git the repository and run the app to see how it works and then
dig into the code.

Note: the javascript library used in the example app is prototype, but
it is pretty easy to replace it with another library (JQuery, for
example).

This example is perfect. However, for some reason, it isn’t working.
When I click the Add Light link it doesn’t add any fields. Here is
all the relevant code (I think). Basically, for me, project is room,
and task is light.


New room

<%= render :partial => ‘room_form’ %>

<%= link_to "Back to List", rooms_path %>



<% form_for @room do |form| %>
<%= form.error_messages %>

<%= form.label :name %>
<%= form.text_field :name %>

Lights

<% form.fields_for :lights do |light_form| %> <%= render :partial => 'light', :locals => { :form => light_form } %> <% end %>

<%= add_child_link "[+] Add new light", form, :lights %>

<%= form.submit "Submit" %>

<% end %>

<%= form.label :wattage, "Wattage of lights: " %> <%= form.text_field :wattage, :size => 2 %>
<%= form.label :quantity, "Number of lights: " %> <%= form.text_field :quantity, :size => 2 %>
<%= form.label :hours_used_per_day, "Number of hours per day lights are on: " %> <%= form.text_field :hours_used_per_day, :size => 2 %>
<%= remove_child_link "remove", form %>



app/helpers/application_helper.rb

Methods added to this helper will be available to all templates in

the application.
module ApplicationHelper
def remove_child_link(wattage, form)
form.hidden_field(:_delete) + link_to_function(wattage,
“remove_fields(this)”)
end

def add_child_link(wattage, form, method)
fields = new_child_fields(form, method)
link_to_function(wattage, h(“insert_fields(this, “#{method}”, “#
{escape_javascript(fields)}”)”))
end

def new_child_fields(form_builder, method, options = {})
options[:object] ||=
form_builder.object.class.reflect_on_association(method).klass.new
options[:partial] ||= method.to_s.singularize
options[:form_builder_local] ||= :form
form_builder.fields_for(method, options[:object], :child_index =>
“new_#{method}”) do |form|
render(:partial => options[:partial], :locals => { options
[:form_builder_local] => form })
end
end
end


Any idea why add_child_link isn’t working?

Thanks,
Ryan

Yes, I have them included in the rooms.html.erb and it shows in the
source of the page. I don’t have an application.html.erb. I also
tried moving the code from application_helper to rooms_helper, which
didn’t help.

I don’t really understand where application comes from anyway. I
didn’t generate anything called application.

Can you verify that you are including the default javascripts in your
template (application.html.erb, most likely).

<% javascript_include_tag :defaults %>

I figured it out. I hadn’t put the functions into application.js.

ryan8720 wrote:

I figured it out. I hadn’t put the functions into application.js.

Cool, good work!

Thanks for all the help so far. I believe I’m starting to understand
things now. The part above is working great. However, I have a
controller called calculator which is the only part that will be
accessible to users. From calculator you enter information about the
house, then that information is saved to house and you can then start
adding rooms, have a house_id attribute that needs to be passed from
the house that was just created.

The problem now is that I can’t get the new room stuff to render from
calculator. It always complains it can’t find the partials (which are
located under app/views/rroms). If I change the paths for them to be
found, it causes other errors.

Here is the calculator_controller. save_house is called when the user
submits the form. The commented line under “if @house.save” is what I
had originally. The line under that is my attempt to fix these
problems.


class CalculatorController < ApplicationController
def index
end

def save_house
@house = House.new(params[:house])
respond_to do |format|
if @house.save
#format.html { render :action => ‘add_rooms’, :id => @house }
format.html { render :template => ‘/rooms/new’, :room_id =>
@house.id }
format.xml { render :xml => @house, :status
=> :created, :location => @house }
else
format.html { render :action => ‘index’ }
format.xml { render :xml => @house.errors, :status
=> :unprocessable_entity }
end
end
end

def add_rooms
@house = House.find(params[:id])
@rooms = Room.find_by_house_id(@house.id)

rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before adding rooms”
redirect_to :action => ‘index’
end

def add_room
@house = House.find(params[:id])
@room = Room.new(params[:room])

respond_to do |format|
  #if @room.valid? && @light.valid? && @house.valid? && @room.save

&& @light.save && @house.add_room(@room) && @house.save
if @room.save
@house.add_room(@room)
@house.save
flash[:notice] = “Room “#{@room.name}” was successfully
added.”
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room, :status
=> :created, :location => @room }
else
format.html { render :action => ‘add_rooms’ }
format.xml { render :xml => @room.errors, :status
=> :unprocessable_entity }
end
end
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before adding a room”
redirect_to :action => ‘index’
end

def report
flash[:notice] = nil
@house = House.find(params[:id])
@rooms = Room.find_by_house_id(@house.id)
rescue ActiveRecord::RecordNotFound
logger.error(“Attempt to access invalid house #{params[:id]}”)
flash[:notice] = “You must create a house before generating a
report”
redirect_to :action => ‘index’
end

end

Preferably I’d like to be able to render add_rooms (see below), which
is just the same partial called form room.new with a list of rooms
above and a button to move on below.


House id is <%= @house.id %>

Your rooms:

<% if @house.rooms %>
    <% for room in @house.rooms %>
  • <%= h room.name %> has <%= h room.number_of_bulbs %> <%= h room.wattage_of_bulbs %> watt bulbs, in use for <%= h room.usage_hours %> hours per day.
  • <% end %>
<% else %>

You have not added any rooms yet

<% end %>

<%= render :partial => ‘rooms/room_form’ %>


<%= button_to "Continue to report", :action => "report", :id => @house %>
----------------------------------------

Thanks,
Ryan

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