Rails - Feb 2006 - Adding children via small subform

I''ve read AWDR and especially the part concerning adding child
line_items to an order.  Unfortunately I want to do my process in
reverse and in doing what I thought would work I get a null object error
when trying to append the children to the parent.

This is a _major_ stumbling block in my Rails use as almost every one of
my projects has needed this so its a pretty vital problem I need to
overcome.

My two tables:
Reviews -< Pictures
(Parent) -< (Child)

I have a form where you first add a Review and after clicking an Ajax
link it produces a sub-form ready for inputting the child pictures.
However, no matter whether I want just one child or a group of children
on the form I can''t seem to get the Child objects to
''<<'' (append) to
the parent object.

In the book you collect your cart of ''children'' (line_items)
then append
these after creating an order.

My code is (in this instance I try it with just a single child):
@picture = Picture.new(params[:picture])
@review = Review.new(params[:review])
@review.pictures << @picture.pictures

I''m totally at a loss and I''m on hands and knees.  Please
please help
me.  I want to go far with Rails and this is killing me.

Thank you for reading.

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

If I understand your problem correctly (and I''m not sure that I do, so
please excuse me if that''s the case), you shouldn''t need to be
appending your ''children'' to the parent in that fashion.

Try instead doing something like
@review = Review.new(params[:review])
@review.save
@picture = Picture.new(params[:picture])
@picture.review_id = @review.id
@picture.save

That will give you a new ''review'' record, plus a new
''picture'' record
with the review_id field in the ''picture'' record pointing to
the
''review'' record.

There may be a more elegant way of achieving the same thing, but
hopefully this is clear enough and addresses the issue you''re seeing.

Regards

Dave M.

On 09/02/06, Doug Bromley <doug.bromley@gmail.com>
wrote:
> I''ve read AWDR and especially the part concerning adding child
> line_items to an order.  Unfortunately I want to do my process in
> reverse and in doing what I thought would work I get a null object error
> when trying to append the children to the parent.
>
> This is a _major_ stumbling block in my Rails use as almost every one of
> my projects has needed this so its a pretty vital problem I need to
> overcome.
>
> My two tables:
> Reviews -< Pictures
> (Parent) -< (Child)
>
> I have a form where you first add a Review and after clicking an Ajax
> link it produces a sub-form ready for inputting the child pictures.
> However, no matter whether I want just one child or a group of children
> on the form I can''t seem to get the Child objects to
''<<'' (append) to
> the parent object.
>
> In the book you collect your cart of ''children''
(line_items) then append
> these after creating an order.
>
> My code is (in this instance I try it with just a single child):
> @picture = Picture.new(params[:picture])
> @review = Review.new(params[:review])
> @review.pictures << @picture.pictures
>
> I''m totally at a loss and I''m on hands and knees.  Please
please help
> me.  I want to go far with Rails and this is killing me.
>
> Thank you for reading.
>
> --
> Posted via http://www.ruby-forum.com/.
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