Rails - Oct 2006 - Creating a new object with multiple associations

This is a pretty simple question but I haven''t heard an answer for it
yet.

Let''s say that a Bid object belongs_to both an Auction and a User at
the same time.  To create a new object I could do something like
user.bids.build which would associate the new bid with that user, or
auction.bids.build which would associate the new Bid with the Auction,
but I have no idea how to create a new bid that would be associate with
both at the same time.  I can of course force-feed the new bid object
with the id of the Auction or User objects, but that is the stupid way
to do it.

This is probably a very newb question, but it never came up with me
before, and I don''t remember reading about it anywhere.


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk
-~----------~----~----~----~------~----~------~--~---

Eleo wrote:
> Let''s say that a Bid object belongs_to both an Auction and a User
at
> the same time.  To create a new object I could do something like
> user.bids.build which would associate the new bid with that user, or
> auction.bids.build which would associate the new Bid with the Auction,
> but I have no idea how to create a new bid that would be associate with
> both at the same time.  I can of course force-feed the new bid object
> with the id of the Auction or User objects, but that is the stupid way
> to do it.
Rather than explictly setting the Bid object''s foreign key, either
add the Bid object to the collection or assign the associated object:

@auction.bids << @user.bids.build(params[:bid])

or

@bid = @user.bids.build(params[:bid])
@bid.auction = @auction
@bid.save!

-- 
We develop, watch us RoR, in numbers too big to ignore.


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk
-~----------~----~----~----~------~----~------~--~---

Hmm I guess that will work.  I like the first example because it uses
less lines.


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk
-~----------~----~----~----~------~----~------~--~---

On 10/24/06, Mark Reginald James
<mrj-bzGI/hKkdgQnC9Muvcwxkw@public.gmane.org>
wrote:
>
> Eleo wrote:
>
> > Let''s say that a Bid object belongs_to both an Auction and a
User at
> > the same time.  To create a new object I could do something like
> > user.bids.build which would associate the new bid with that user, or
> > auction.bids.build which would associate the new Bid with the Auction,
> > but I have no idea how to create a new bid that would be associate
with
> > both at the same time.  I can of course force-feed the new bid object
> > with the id of the Auction or User objects, but that is the stupid way
> > to do it.
>
> Rather than explictly setting the Bid object''s foreign key, either
> add the Bid object to the collection or assign the associated object:
>
> @auction.bids << @user.bids.build(params[:bid])
>
> or
>
> @bid = @user.bids.build(params[:bid])
> @bid.auction = @auction
> @bid.save!
>
I''d personally prefer something more semantically meaningful, thus
delegating the creation and association of a bid to the model domain:

class User < ...

  def bids_on(auction, bid_params)
    bid = Bid.new(bid_params)
    bid.auction = auction
    bid.user = self
    bid.save!
  end

end

And then in your controller:

@user.bids_on(auction, params[:bid])

This makes it immediately obvious what''s going on, and the
implementation details are neatly encapsulated in the model.

Cheers,
Max

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk
-~----------~----~----~----~------~----~------~--~---