Active Record two belongs_to calls or single table inheritance
- by ethyreal
In linking a sports event to two teams, at first this seemed to make sense:
events
- id:integer
- integer:home_team_id
- integer:away_team_id
teams
- integer:id
- string:name
However I am troubled by how I would link that up in the active record model:
class Event
belongs_to :home_team, :class_name => 'Team', :foreign_key => "home_team_id"
belongs_to :away_team, :class_name => 'Team', :foreign_key => "away_team_id"
end
Is that the best solution?
In an answer to a similar question I was pointed to single table inheritance, and then later found polymorphic associations. Neither of which seemed to fit this association. Perhaps I am looking at this wrong, but I see no need to subclass a team into home and away teams since the distinction is only in where the game is played. If I did go with single table inheritance I wouldn't want each team to belong_to an event so would this work?
# app/models/event.rb
class Event < ActiveRecord::Base
belongs_to :home_team
belongs_to :away_team
end
# app/models/team.rb
class Team < ActiveRecord::Base
has_many :teams
end
# app/models/home_team.rb
class HomeTeam < Team
end
# app/models/away_team.rb
class AwayTeam < Team
end
I thought also about a has_many through association but that seems two much as I will only ever need two teams, but those two teams don't belong to any one event.
event_teams
- integer:event_id
- integer:team_id
- boolean:is_home
Is there a cleaner more semantic way for making these associations in active record? or is one of these solutions the best choice?
Thanks
