Validation of other model fields

I've got in my Form not only fileds from my model but also fields from
ither models. How can I validate them like other fields.

Example names od input tag fields

<p><label for="model1_name1">Name1</label>
<%= text_field 'model1', 'name1' , :size => 40 %></p>

<p><label for="model1_name2">Name2</label>
<%= text_field 'model1', 'name2' , :size => 40 %></p>

and from different model:

<p><label for="model2_name3">Name3</label>
<%= text_field 'model2', 'name3' , :size => 40 %></p>

How can I validate presence_of field name3 from model2 model??

The update_attributes method saves as well as updating the attribute.

b

Stephan Wehner wrote:

Daniello, hopefully the following will help move you forward. It will leave you with an @errors for both models in your view that you can iterate over

When managing validations for multiple models in one action I typically use something like the following:

     @model1 = Model1.new(params[:model1])
     @model2 = Model2.new(params[:model2])

     respond_to do |format|
       if @ model1.valid? && @ model2.valid?
         #TODO: transaction here would help out
         @ model1.save(false)
         flash[:notice] = 'Model1 and Model2 were successfully created.'
         format.html { render :partial => "my_partial" }
       else
         flash[:notice] = 'There were errors validating model1, model2'
         #merge_errors (below), merges the errors of 2 models into one errors list
         format.html { @errors = merge_errors(@model1, @model2); render :partial => "/error_messages", :errors => @errors, :status => 500 }
       end
     end

   #merges errors from 2 instances into 1 error object
   def merge_errors(model1, model2)
     if model1.errors.size > 0 && model2.errors.size > 0
       model1.errors.instance_eval { @errors.merge model2.errors.instance_values['errors'] }
     elsif model1.errors.size > 0
       model1.errors
     elsif model2.errors.size > 0
       model2.errors
     else
       model1.errors
     end
   end

Cheers,
Jodi
General Partner
The nNovation Group inc.
www.nnovation.ca/blog

on-innovation.gif

Daniello,

If there is a model association between the two models you can use the
following (copy/pasted from api.rubyonrails.org):

validates_associated(*attr_names)

Validates whether the associated object or objects are all valid
themselves. Works with any kind of association.

  class Book < ActiveRecord::Base
    has_many :pages
    belongs_to :library

    validates_associated :pages, :library
  end

Warning: If, after the above definition, you then wrote:

  class Page < ActiveRecord::Base
    belongs_to :book

    validates_associated :book
  end

...this would specify a circular dependency and cause infinite
recursion.

NOTE: This validation will not fail if the association hasn't been
assigned. If you want to ensure that the association is both present
and guaranteed to be valid, you also need to use
validates_presence_of.

Configuration options:

    * on Specifies when this validation is active (default is :save,
other options :create, :update)
    * if - Specifies a method, proc or string to call to determine if
the validation should

occur (e.g. :if => :allow_validation, or :if => Proc.new { |user|
user.signup_step > 2 }). The method, proc or string should return or
evaluate to a true or false value.

Regards,
Bas van Westing

now how did I miss that ?!

This is clearly a better route to go - for you and me, Daniello.

thanx Bas

Jodi