Rails - Aug 2006 - Create several models at once and validating

I have two models User and Team. Also I have a register form where the 
new
user fill in her data and choose a name for a Team.

Well, in the user model there are several validations which work fine, 
but
team model also have a validation for a uniqueness name that doesn''t 
fire up
when she gives an existent team''s name.

This is the flow it follows:

/user/new -> it shows a form to fill user''s data and a
team''s name ->
Create ->
UserController
  def create
    @user = User.create(params)
    if request.post? and @user.save
     ......
    end
  end

User
  validates_uniqueness_of :username <--- THIS WORKS FINE
  def self.create
    user = User.new(params[:user])
    team = Team.new(params[:team])
    user.team = team
    user
  end

Team
  validates_uniqueness_of :name <--- THIS DOESN''T WORK

What am I doing wrong?

-- 
Posted via http://www.ruby-forum.com/.

>
> /user/new -> it shows a form to fill user''s data and a
team''s name ->
> Create ->
> UserController
>   def create
>     @user = User.create(params)
>     if request.post? and @user.save
>      ......
>     end
>   end
>
> User
>   validates_uniqueness_of :username <--- THIS WORKS FINE
>   def self.create
>     user = User.new(params[:user])
>     team = Team.new(params[:team])
>     user.team = team
>     user
>   end
This is bad. Your model should not be dependent on the View or the
Controller - by using the params hash in your model code, you are
restricting your model to only work in a request context. This
prevents you from using User.create anywhere but from a controller
that is called from a form that has a :users parameter set. You are
also changing the semantics of the create method, which by convention
performs a save of the model.
You should also be wrapping the two save operations in a transaction.

Should be rewritten as:

class UserController
def create
    @user = User.new(params[:user])
    @team = Team.new(params[:team])
    User.transaction do
      success = @user.save
      success &= @team.save
      if success
        flash[:notice] = ''User was successfully created.''
        redirect_to :action => ''list''
      else
        render :action => ''new''
      end
    end
  end
...

The "success" stuff is there so that both models get a chance to
validate themselves (which happens on save).

In your view, you will need to also add error output for the @team
model instance. By default, the scaffolding assumes that there is a
single model object for a controller and view:

<%= error_messages_for ''team'' %>
<%= error_messages_for ''user'' %>

Max

> This is bad. Your model should not be dependent on the View or the
> Controller - by using the params hash in your model code, you are
> restricting your model to only work in a request context. 
Yes, you''re absolutely right, I''ve already change it.
> class UserController
> def create
>     @user = User.new(params[:user])
>     @team = Team.new(params[:team])
>     User.transaction do
>       success = @user.save
>       success &= @team.save
>       if success
>         flash[:notice] = ''User was successfully created.''
>         redirect_to :action => ''list''
>       else
>         render :action => ''new''
>       end
>     end
>   end
But I don''t want this behaviour. I forgot to mention that User and Team
are related:

User                              Team
  has_one :team <-------------->    belongs_to :user

Thus I did @user.team = @team then @user.save that saves my user and the
related team too.

But if I do @user.save and then @team.save, whether validations on team 
failed,
the user is created but team doesn''t and I want non of them to be
saved.


-- 
Posted via http://www.ruby-forum.com/.

You can ensure that the models are both valid, e.g. with .valid? first.

-- 
Posted via http://www.ruby-forum.com/.

kris wrote:
> You can ensure that the models are both valid, e.g. with .valid? first.
Thanks, that''s the way I resolved it, just now I was going to post it.

-- 
Posted via http://www.ruby-forum.com/.

You can call validation first, and proceed to saving
only if everything validates:

if @user.valid? && @team.valid?
  @user.save(false)
  @team.save(false)
end

the ''valid?'' method does what you''d expect; the
''false'' paramter to the save method means "don''t
do
validation while saving" (since by the time you get to
the save statement, the validation has already
passed).

Cheers,
B Gates


But if I do @user.save and then @team.save, whether
validations on team 
failed,
the user is created but team doesn''t and I want non of
them to be 
saved.

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B Gates wrote:
> You can call validation first, and proceed to saving
> only if everything validates:
> 
> if @user.valid? && @team.valid?
>   @user.save(false)
>   @team.save(false)
> end
The only potential problem with this code is that you won''t get
any @team error messages in the view if @user fails to validate.
Instead you''d have to write:

   valid_team = @team.valid?
   if @user.valid? && valid_team

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