# Basic has\_many question **URL:** \ **Category:** Rails\ **Created:** [December 6, 2006, 1:31am UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474 "2006-12-06T01:31:22Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 6, 2006, 1:31am UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/1 "2006-12-06T01:31:22Z")
Hi there, I’m still new at this, but I’m creating a quick little foosball stats app for my office(!) and I have a question about relationships. I have a table called games and a table called players. I’d like it so when people enter information about a game they can choose from four dropdowns the four players that played in the game. At first I wasn’t thinking and thought it would be a basic thing like this: game.rb has\_many :players and player.rb belongs\_to :game But then I couldn’t figure out how to link four players to one game. Am I missing something really obvious? Is this a habtm instance? Thanks! ---
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 6, 2006, 2:11am UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/2 "2006-12-06T02:11:22Z")
Assuming that players play in more than one game and games have more than one player, it is a has\_and\_belongs\_to\_many situation, yes. ---
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 6, 2006, 6:04am UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/3 "2006-12-06T06:04:20Z")
The link that connects an instance of 4 players to a particular game is called a Match. Different sports have different names for it, in cricket it is a Test Match, in tennis it is a Match. So use the terminology that is used in your foosball domain. All the relevant data for that particular Match will go into that table, for instance the stadium name, date of the game, whether the Match was sold out etc. This is in addition to the foreign keys that connect the other two classes. You will have this association table with just the foreign keys if your app does not need any other data mentioned above. ---
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 6, 2006, 4:43pm UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/4 "2006-12-06T16:43:48Z")
Consider a join table, using “has\_many :through” constructs. This allows you to record particulars of that players involvment in the game (team, position, etc). I believe this is what Dave was suggesting with the ‘match’ table, though match and game sound synonymous, and I’d use someting to indicate involvement, like ‘encounters’ (derived from a verb) encounter.rb belongs\_to :player belongs\_to :game player.rb has\_many :encounters has\_many :games, :through =\> encounters game.rb has\_many :encounters has\_many :players, :through =\> encounters See the rails docs on ‘has\_many’, and Susser’s writings on associations: [http://blog.hasmanythrough.com/articles/category/associations](http://blog.hasmanythrough.com/articles/category/associations) , for more info. ---
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 6, 2006, 4:59pm UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/5 "2006-12-06T16:59:52Z")
If the application requires you to record details that relates the game and players in the encounter, then you can use has\_many :through. Otherwise habtm relationship will suffice. ---
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 7, 2006, 7:50am UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/6 "2006-12-07T07:50:12Z")
Actually question leads to more important domain-designing issues: 1. Are players on fixed teams? (this is easier, btw) 2. How do you record wins? For fixed teams, I would go with: Class Players #this assumes you can be on more than one team have\_and\_belong\_to\_many :teams Class Teams have\_and\_belong\_to\_many :players have\_and\_belong\_to\_many :matches Class Matches have\_and\_belong\_to\_many :teams Then the Matches table migration would be: t.column :team1\_id, :integer, :null =\> false t.column :team2\_id, :integer, :null =\> false t.column :winner\_id, :integer, :null =\> false t.column :team1\_score, :integer, :null =\> false t.column :team2\_score, :integer, :null =\> false t.column :played\_at, :datetime, :null =\> false #plus some foreign key mapping that I can’t be bothered to do ---
**Author:** ![daveamos](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/a698b9/32.png) [@daveamos](https://www.ruby-forum.com/u/daveamos)\ **Post date:** [December 7, 2006, 7:51am UTC](https://www.ruby-forum.com/t/basic-has-many-question/78474/7 "2006-12-07T07:51:11Z")
of course those should be ‘has\_and\_belongs\_to\_many’