Rails - Oct 2007 - converting from HABTM to has_many :through

Hello,

I have a has_and_belongs_to_many relationship that I''ve realized I need
to add additional attributes to. So I''m converting it to a has_many
:through (HMT) relationship. This is the first time I''ve used an HMT,
and it seems like I''m using too much code. I couldn''t figure
out how to
get the join model objects to update automatically as a result of
updating the primary object, so I''ve ended up doing individual
saves/updates on each join model object.

The story is a regatta can include many boat classes, and a boat class
can be included in many regattas.

class Regatta < ActiveRecord::Base
  has_many :inclusions
  has_many :boat_classes, :through => :inclusions
  has_and_belongs_to_many :users
end

class BoatClass < ActiveRecord::Base
  has_many :inclusions
  has_many :regattas, :through => :inclusions
end

class Inclusion < ActiveRecord::Base
  belongs_to :regatta
  belongs_to :boat_class
end

Eventually, I''ll attach a fee to each boat_class when it gets included
in a regatta. But for now I''m just trying to get back to the same
functionality I had when it was a HABTM relationship, and there was no
"include" model. So, here is what the update method looks like now:

    @regatta = Regatta.find(params[:id])
    Inclusion.find_all_by_regatta_id(params[:id]).each { |i|
        boat_class = i.boat_class
        if params[:boat_classes]
            i.included = params[:boat_classes].include? boat_class.id
            params[:boat_classes].delete boat_class.id
        else
            i.included = false
        end
        flash[:notice] = ''inclusion failure'' if !
i.update_attribute(:included, i.included)
    }
    params[:boat_classes].each { |boat_class_id|
        boat_class = BoatClass.find boat_class_id
        logger.info "*** boat class #{boat_class.name} inclusion not
found"
        @regatta.inclusions << Inclusion.new { |i|
            i.boat_class_id = boat_class_id
            i.included = true
            flash[:notice] = ''inclusion failure'' if ! i.save
        }
    } if params[:boat_classes]
    @regatta.users = User.find(params[:users]) if params[:users]
    if @regatta.update_attributes(params[:regatta])
      flash[:notice] = ''Regatta was successfully updated.''
      redirect_to :action => ''show'', :id => @regatta
    else
      render :action => ''edit''
    end

It seems to me that I shouldn''t have to individually update all the
existing inclusions, or manually create & save the new ones. I''d
like
suggestions for how I can reduce the amount of code here. Considering
that the first 20 lines used to simply be:

    @regatta = Regatta.find(params[:id])
    @regatta.boat_classes = User.find(params[:boat_classes]) if
params[:boat_classes]


Additional background info: a) this keeps the join model objects around
even when a boat_class gets excluded, so that it''s attributes will be
saved. That''s not critical, if I can have it be much tighter,
I''m happy
to give that up. b) there is a bug in this that I haven''t found yet,
but
is irrelevant to this question: this code creates a new inclusion even
when there is an existing one found already. It seems params[...].delete
is not working the way I expect it to.

Thanks for any help,
Avram
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