Parent model running validations on all existing children

rubyonrails-talk
1

In my application, a Language has many Phrases. Here is my code:

#language model has_many :phrases accepts_nested_attributes_for :phrases

#phrase model validates_presence_of :value belongs_to :language

#languages controller def edit    @language = Language.find(params[:id])    # Let's say we only want to update some of the phrases (e.g. by category, date, etc)    @phrases = @language.phrases.all(:limit => 3) end

def update    @language = Language.find(params[:id])    if @language.update_attributes(params[:language])      flash[:notice] = "Successfully updated language."      redirect_to edit_language_path(@language)    else      render :action => 'edit'    end end

# project edit view <% form_for @language do |f| %> <%= f.error_messages %> <p>    <%= f.label :name %><br />    <%= f.text_field :name %> </p> <% f.fields_for :phrases, @phrases do |phrases_form| %>    <p>      <%= phrases_form.label :value %>      <%= phrases_form.text_field :value %>    </p> <% end %> <p><%= f.submit %></p> <% end %>

When I submit the form, if at least one of the phrases being saved is an existing record, every single phrase corresponding to @language will be validated, instead of running validations only in the three phrases being updated. That problem isn't present when all of the phrases being saved are new records.

2

I was expecting Rails to only validate the phrase that is being updated, here you can see it's validating all of the existing phrases:

$ script/console Loading development environment (Rails 2.3.5)

lang = Language.first

=> #<Language id: 1, name: "Italiano">

lang.phrases

=> [#<Phrase id: 7, value: "Buona notte", language_id: 1>, #<Phrase id: 10, value: "Ciao", language_id: 1>, #<Phrase id: 11, value: "Prego", language_id: 1>]

lang.phrases_attributes = [{:id => "7", :value => "Buon giorno"}]

=> [{:value=>"Buon giorno", :id=>"7"}]

lang.save

Validating: Buon giorno

Validating: Ciao

Validating: Prego

=> true

My models, again, now with the added "before_validation" callback:

class Language < ActiveRecord::Base   has_many :phrases   accepts_nested_attributes_for :phrases end

class Phrase < ActiveRecord::Base   validates_presence_of :value   belongs_to :language   def before_validation     logger.debug "\nValidating: #{self.value}\n"   end end

Validating all phrases is a real problem in my app, as I have tens of thousands; Is there a way to avoid this? Is this normal behavior for Rails?

Ruben Ascencio wrote: