Rails - May 2008 - habtm or two foreign keys?

Somehow I keep running into this problem in different projects ..

Say I want to represent soccer matches. A Match is associated with
exactly two Teams, and keeps the score each team achieved. I see two
choices:

a) add two foreign keys to Match and have it belong_to :team_a and
:team_b

pro: it is easy to match score_a to team_a and score_b to team_b, and it
is innately impossible to associate too many teams

con: I would need two rather ugly has_many associations in the Team
model, as in "has_many :team_a_matches / has_many :team_b_matches"
(right?)

b) use habtm

pro: nice and clean associations

con: associating score_a and score_b attributes in the Match model with
exactly the right team from Match#teams gets convoluted and error-prone,
and association validation is a bit more involved

How would you proceed? Am I missing a third option?

Thanks in advance,
Jan
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I think you want this:

class Match < ActiveRecord::Base
  belongs_to :team
end

class Team < ActiveRecord::Base
  has_many :games, :foreign_key => :away_team
  has_many :games, :foreign_key => :home_team
end

Then you can do
Team.find(1).games #displays home and away games
Game.find(1).home_team
Game.find(1).away_team

ESPNDev

On May 1, 1:50 pm, Jan Foeh
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Somehow I keep running into this problem in different projects ..
>
> Say I want to represent soccer matches. A Match is associated with
> exactly two Teams, and keeps the score each team achieved. I see two
> choices:
>
> a) add two foreign keys to Match and have it belong_to :team_a and
> :team_b
>
> pro: it is easy to match score_a to team_a and score_b to team_b, and it
> is innately impossible to associate too many teams
>
> con: I would need two rather ugly has_many associations in the Team
> model, as in "has_many :team_a_matches / has_many
:team_b_matches"
> (right?)
>
> b) use habtm
>
> pro: nice and clean associations
>
> con: associating score_a and score_b attributes in the Match model with
> exactly the right team from Match#teams gets convoluted and error-prone,
> and association validation is a bit more involved
>
> How would you proceed? Am I missing a third option?
>
> Thanks in advance,
> Jan
> --
> Posted viahttp://www.ruby-forum.com/.
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Thanks for your input! I don''t really have the distinction into home
and
away teams - I''m building a small app for the upcoming Euro Cup - but
it
may be best to pretend I had and be done with it.
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