Editing Multiple Models in One Form (Page 2 of 4)

Which part specifically are you attempting to move into a partial? The instance variables (@task or @project) should be accessible from the partial (I think). Are you not able to access them?

You could pass variables to the partial using the :locals parameter, however, some of these methods (such as error_messages_for) rely on the use of an instance variable instead of a local variable so it makes things a little more difficult. It's hard to say the best approach without knowing which part of the form you would like in the partial.

I am using acts_as_attachment to upload 4 images and everything works great on that side. But I also want to be able to edit the form and the images. I have went through the tutorial but can not seem to get this to work. Does anyone know how I can go about doing this?
Thanks,

Re: Transactions

From playing around with the code, this apparently will wrap everything into one transaction:

Project.transaction do
  @project.save!
  @project.tasks.each(&:save!)
end

I wasn't sure this would work as the tasks are a different model, but looking at the development log, it is all put into one BEGIN/COMMIT block.

Last edited by boone (2007-04-29 18:30:59)

You are missing an opening bracket on the "tr" tag here:

  <% fields_for "professor[]" do |f| %>
  tr><td><br/><br/></td></tr>
  <tr>
  <td><div align="right">?????</div></td>
  <td><div align="left"><%= f.text_field :name %></div></td>
  </tr>
  <% end %>

Does that fix the problem?

<tr><td><br/><br/></td></tr>

How did you generate the tasks table? Does it have a project_id column?

thanks for the response, and the great tutorial. I didn't have product_id added. Have you included your migrations somewhere, or explicitly indicated what the database should look like? If not, I think it might be an important addition which would complete your lessons nicely...perhaps I've just missed it...

The first, I assumed, looks like this:
class Projects < ActiveRecord::Migration
  def self.up
    create_table :projects  do  |t|
      t.column  :project_id,  :integer
      t.column  :name,  :string
  end
end

  def self.down
    drop_table  :projects
  end
end

....and the second, like:

class Tasks < ActiveRecord::Migration
  def self.up
    create_table  :tasks  do  |t|
      t.column  :name,  :string
  end
end
  def self.down
    drop_table  :tasks
  end
end

....am I close?

I don't understand this line:

   @project.tasks.each { |t| t.attributes = params[:task][t.id_to_s] }

The request has "params" hash.  That hash contains an array of tasks.  Hence, params[:task] refers to that array and the [t.id_to_s] indicates which task in the array.  HOWEVER, the array indices should be 0 to # of tasks.  It's not the task ID.  That's why I don't understand why t.id_to_s would work.

For one, in my code, I get an error: undefined method `id_to_s`  Secondly, if this is changed to id.to_s, it doesn't work either.  What is the problem here?

Last edited by robertl (2007-07-07 20:56:43)

Hi, I'm having a problem with my application when following the steps in the tutorial.

Basically I have this update method in my controller:

  def update
    @recipe = Recipe.find(params[:id])
    @recipe.attributes = params[:recipe]
    @recipe.directions.each { |d| d.attributes = params[:directions][d.id.to_s] }


    if @recipe.valid? && @recipe.directions.all?(&:valid?)
      @recipe.save!
      @recipe.directions.each(&:save!)
      redirect_to :action => 'show', :id => @recipe
    else
      render :action => 'edit'
    end
  
  end

And this is how my view looks:

<p><label for = 'direction'>Directions</label><br/ ></p>
<table>
<% @recipe.directions.each_with_index do |direction, index| %>
<tr>
    <% fields_for "directions[#{index}]", direction do |d| %>
        <td><%= d.text_field :direction, :size => 80 %></td>
    <% end %>
</tr>
<% end %>

I am able to save a list of directions, but when trying to update or add new directions to an existing list, nothing ever gets updated. I checked the SQL statements in the log and it only seems to be updating the list with the old contents. I've spent a while playing around with this, but I don't know what's going on or how to debug it. Any help would be greatly appreciated!

The author of this series of tutorials is a life saver. I would like to show you all what my update method looks like and its helper methods

Here is the update method.
----------------------------

  def update
    @person = Person.find(params[:id])
    @person.attributes = params[:person]
    
    redefine_save_to_destroy_removed_associations(params, @person, :emails)
    redefine_save_to_destroy_removed_associations(params, @person, :phone_numbers)
    redefine_save_to_destroy_removed_associations(params, @person, :addresses)
    
    update_existing_associations(params, @person, :emails)
    update_existing_associations(params, @person, :phone_numbers)
    update_existing_associations(params, @person, :addresses)
    
    build_populated_associations(params, @person, :emails, [:address])
    build_populated_associations(params, @person, :phone_numbers, [:phone_number])
    build_populated_associations(params, @person, :addresses, [:street1, :street2, :city, :zip])    
        
    if @person.valid?
      Person.transaction do
        @person.save!
        @person.emails.each(&:save!)
        @person.addresses.each(&:save!)
        @person.phone_numbers.each(&:save!)
      end
      redirect_to :action => 'show', :id => @person
    elsif
      render :action => 'edit'
    end
  end

Helper methods in application.rb.
----------------------------

  def build_populated_associations(params, model, association, fields)
    singular = Inflector.singularize(association)
    unless params[singular].nil?
      params[singular].delete_if do |key, value|
        blanks = fields.collect { |field| value[field].blank? }  
        !blanks.include?(false)
      end
      
      params[singular].each_value do |value|
        model.send(association).build(value) if value[:id].blank? 
      end
    end
  end
  
  def update_existing_associations(params, model, association)
    singular = Inflector.singularize(association)
    model.send(association).each do |assoc|
      attrs = assoc.attributes
      unless params[singular].nil?
        params[singular].each_value do |value|
          if value[:id] == assoc.id.to_s
            attrs = value
            break
          end
        end
        
        assoc.attributes = attrs
      end
    end  
  end
  
  def redefine_save_to_destroy_removed_associations(params, model, association)
    singular = Inflector.singularize(association)
    param_ids = []
    unless params[singular].nil?
      param_ids = params[singular].values.collect do |value|
        value[:id]
      end
    end
    
    model.send(association).each do |a|
      id = a.id.to_s
      unless param_ids.include?(id)
        def a.save!
          destroy
        end
      end
    end    
  end

Last edited by jwheeler (2007-07-20 23:10:39)