From: Jason Foreman <threeve.org@...>
Date: 2005-06-07T22:24:02+09:00
Subject: Re: Rails/ActiveRecord Nuby question.

On 6/6/05, Harold Hausman <hhausman@gmail.com> wrote:
> ..
> class Match < ActiveRecord::Base
>         has_one :team_one, :class_name => "Team", :conditions => 'id = #{one}'
>         has_one :team_two, :class_name => "Team", :conditions => 'id = #{two}'
> end
> 
> *note: 'one' and 'two' are the names of the columns in the matches
> table where I store the team ids that participated in the match.
> 
> What I was hoping was that each Match object would then have two new
> child objects called team_one and team_two which would be Team
> objects. This did not work, near as I can tell it formulated some sql
> string which contained some match_id gibberish in the where clause and

You want to have:
class Match < ActiveRecord::Base
   belongs_to :team_one, ...
   belongs_to :team_two, ...
end

belongs_to signifies that the foreign key column is in THIS table, ie
the table of the same model.  has_one signifies that the foreign key
column is in the table of the related model.

Very common mistake.  But I believe there is significant documentation
to explain why the relations are named as they are though.

Hope that helps.

BTW, there is a mailing list specifically for Ruby On Rails [1], which
would be more appropriate for these questions than ruby-talk.

Jason


[1] http://lists.rubyonrails.org/mailman/listinfo/rails