Has and belongs to many

rubyonrails-talk
1

Hello, I've searched but I can't find a good tutorial to has and belongs to many.

What should both of my models, Games and Players, look like if a game has many players and a player has many games.

Also when I create I want to be able to associate the player with the game. Before I was doing @game.save    for player in @home.players             player.game_id = @game             player.increment! :games    end

What should I do now to make the association? Also how do I find all players by game_id?

2

Doing player.game_ids = @game gives undefined method `reject' for 1:Fixnum

3

Hello, I've searched but I can't find a good tutorial to has and belongs to many.

What should both of my models, Games and Players, look like if a game has many players and a player has many games.

http://mboffin.com/stuff/ruby-on-rails-data-relationships.png

4

Also why is increment! not working. By the way @home = Team.find_by_user_id(current_user.id) and team has many players.

5

So if I have a Game a Player and a Team I would want to do Game has many teams (actually only 2) Team has many games all through a Player???

6

The key is, a game is a connection between two teams. So a Games table would consist of three columns: id, home_team_id, away_team_id:

class Game   belongs_to :home_team, :class_name => "Team"   belongs_to :away_team, :class_name => "Team" end

class Player   belongs_to :team end

class Team has_many :games has_many :players end

For example:

cubs = Team.find(1) sox = Team.find(2)

g = Game.create(:home_team => cubs, :away_team => sox)

g.home_team.players # shows players on the Cubs

p = cubs.players.first p.team.games # shows all the games this player is in

Of course, that last bit assumes the player plays in every game the team plays in. If that's not the case for you, you would need to add another table to tracks 'attendance' of the player for each game.

So I've just shown the simple case here, in the hopes it gives you a start in the right direction or is at least food for thought.

Jeff softiesonrails.com