Question

Very new to Rails, have managed a few simple projects, but now stepping into more complex associations between tables and was hoping for some help.

The scenario can best be related to a sports match. Let’s say we have

1) A Team (has_many players)

2) A Player (belongs_to team)

3) A Match — now it gets tricky.

A Match will have: 2 teams, and 22 players (11 on each side) that take part in it. Also, associated with each player, will be their scores for the match (for example, Shots on goal, Goals scored, Points, etc.)

What would be the best practice to create this kind of association? Any tips would be greatly appreciated.

Answer 1

Models

app/models/team.rb

class Team < ActiveRecord::Base
    has_many :players, inverse_of: :team
    has_many :team_matches
    has_many :matches, through: :team_matches
end

app/models/player.rb

class Player < ActiveRecord::Base
    belongs_to :team, inverse_of: :player
    has_many :player_matches
    has_many :matches, through: :player_matches
end

app/models/match.rb

class Match < ActiveRecord::Base
    has_many :players, through: :player_matches
    has_many :teams, through: :team_matches
end

app/models/team_match.rb

class TeamMatch < ActiveRecord::Base
    belongs_to :team
    belongs_to :match
end

app/models/player_match.rb

class PlayerMatch < ActiveRecord::Base
    belongs_to :player
    belongs_to :match
end

Migrations

db/migrate/create_matches.rb

class CreateMatches < ActiveRecord::Migration
  def change
    create_table :matches do |t|
      t.datetime :happened_at
      t.timestamps
    end
  end
end

db/migrate/create_players.rb

class CreatePlayers < ActiveRecord::Migration
  def change
    create_table :players do |t|
      t.string :name
      t.timestamps
    end
  end
end

db/migrate/create_teams.rb

class CreateTeams < ActiveRecord::Migration
  def change
    create_table :teams do |t|
      t.string :name
      t.timestamps
    end
  end
end

db/migrate/create_player_matches.rb

class CreatePlayerMatches < ActiveRecord::Migration
  def change
    create_table :player_matches do |t|
      t.integer :match_id
      t.integer :player_id
      t.integer :player_shots_on_goal
      t.integer :player_goals_scored
      t.timestamps
    end
  end
end

db/migrate/create_team_matches.rb

class CreateTeamMatches < ActiveRecord::Migration
  def change
    create_table :team_matches do |t|
      t.integer :match_id
      t.integer :team_id
      t.integer :team_points
      t.timestamps
    end
  end
end

Edit1: @Mischa should share credit here! 🙂

Edit2: Sorry about the many versions, I totally underestimated this problem.