Rails - Feb 2006 - Another HABTM Question

Hi there,

I have a question on what would be the best way to save a HABTM model.

A posting habtm categories, and a category habtm postings.

class Category < ActiveRecord::Base
     has_and_belongs_to_many :postings
end

class Posting < ActiveRecord::Base
  has_and_belongs_to_many :categories
end

In my blog_controller, where the actual posting is saved, is where I
think I''m having some trouble. Here''s what I currently have to
save a
post:

def create
	@posting = Posting.new(params[:posting])
	body_content = @posting.body
	body_content.gsub!( /(.*)(\n)/, ''\1<br />'' )
	@posting.body = body_content

	@posting.save!
	@posting.user_id = session[:user_id]
	logger.debug("Saving the post.")
	if @posting.save
	  flash[:notice] = ''Posting was successfully created.''
	  redirect_to :controller => ''list'', :action =>
''index''
	else
	  render :action => ''new''
	end
end

I can successfully load all the categories into a multiple selection
box on the page that is creating the posting, but I''m unsure how to
save the posting.id and the category.id into the categories_postings
table within the ''create'' action.

Thank you,
Dave Hoefler

There really needs to be a ''Rails on Relationships'' book for
us geeks ;-)

To save a HABTM relationship you should just have to wire the objects
together correctly and then save either one of them.

So in your case it might be something like:

# let''s say your create function will take in a list of category ids
with
which the new posting should be related:

def create(category_ids)
  cats = Category.find(category_ids)
  @posting = Posting.new(params[:posting])
  body_content = @posting.body
  body_content.gsub!( /(.*)(\n)/, ''\1<br />'' )
  @posting.body = body_content

  @posting.categories = cats
  @posting.save!
  # ... omitted
end


- Byron

On 2/14/06, Dave Hoefler <dhoefler@gmail.com>
wrote:
>
> Hi there,
>
> I have a question on what would be the best way to save a HABTM model.
>
> A posting habtm categories, and a category habtm postings.
>
> class Category < ActiveRecord::Base
>      has_and_belongs_to_many :postings
> end
>
> class Posting < ActiveRecord::Base
>   has_and_belongs_to_many :categories
> end
>
> In my blog_controller, where the actual posting is saved, is where I
> think I''m having some trouble. Here''s what I currently
have to save a
> post:
>
> def create
>         @posting = Posting.new(params[:posting])
>         body_content = @posting.body
>         body_content.gsub!( /(.*)(\n)/, ''\1<br />''
)
>         @posting.body = body_content
>
>         @posting.save!
>         @posting.user_id = session[:user_id]
>         logger.debug("Saving the post.")
>         if @posting.save
>           flash[:notice] = ''Posting was successfully
created.''
>           redirect_to :controller => ''list'', :action
=> ''index''
>         else
>           render :action => ''new''
>         end
> end
>
> I can successfully load all the categories into a multiple selection
> box on the page that is creating the posting, but I''m unsure how
to
> save the posting.id and the category.id into the categories_postings
> table within the ''create'' action.
>
> Thank you,
> Dave Hoefler
>
> There really needs to be a ''Rails on Relationships'' book
for us geeks ;-)
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>


--
Byron
http://byron.saltysiak.com
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