Rails - Jan 2008 - Making an child before the parent is commited to DB

Say I have a model something like this
Parent has_many kids
Kid belongs_to Parent.

Now I have view for say a new Parent. I also have provided an AJAX form
so that they can fill in all the children they have as well.

Whats the best way to go about adding a child to a parent at this stage.
Nothing has been committed to the database. And I can''t add a child to
the database without having a parent. But the parent has not been
created yet.

Thanks in advance for help! ^_^
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Take a look at ActiveRecord transactions.

If your params from the controller are :parent and :kids in your model
method you would do a transaction:

def self.create_family(params)
  Parent.transaction do
    parent = Parent.create(params[:parent])
    params[:kids].each do |kid|
       parent.kids.create(kid)
    end
  end
end

If one of the creates fails, they all get rolled back.

John.





On Jan 3, 9:47 pm, Luke Grimstrup
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Say I have a model something like this
> Parent has_many kids
> Kid belongs_to Parent.
>
> Now I have view for say a new Parent. I also have provided an AJAX form
> so that they can fill in all the children they have as well.
>
> Whats the best way to go about adding a child to a parent at this stage.
> Nothing has been committed to the database. And I can''t add a
child to
> the database without having a parent. But the parent has not been
> created yet.
>
> Thanks in advance for help! ^_^
> --
> Posted viahttp://www.ruby-forum.com/.
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Cheers for that, I think that''ll work.

Another question:
I have bunch of text_fields tags that get pushed onto the form via Ajax 
every time the user hits "add new child" now, if I wanted to add 4
kids
to this family. Then I would have 4 text_fields.

Is it possible to group the text_fields in the view so that I can 
iterate through them in the code-behind?
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Have you seen the Railscast on this subject, I think it more or less
describes what you''re trying to achieve.

http://www.railscasts.com/episodes/75

On 4 Jan, 03:54, Luke Grimstrup
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Cheers for that, I think that''ll work.
>
> Another question:
> I have bunch of text_fields tags that get pushed onto the form via Ajax
> every time the user hits "add new child" now, if I wanted to add
4 kids
> to this family. Then I would have 4 text_fields.
>
> Is it possible to group the text_fields in the view so that I can
> iterate through them in the code-behind?
> --
> Posted viahttp://www.ruby-forum.com/.
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Thanks for sharing that wonderful resource. It looks exactly like the 
thing I''m after!
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