Rails: When to use many to many assocations?

Question

I have been working with rails for almost a year now and I have been in situations where I am not sure when to use the many-to-many association. This is my current situation.

I have a player, season, and sport.

player.rb

has_many :seasons, :dependent => :destroy

season.rb

belongs_to :player
has_many :sports, :dependent => :destroy

sport.rb

belongs_to :season

A player has_many :seasons and season belongs to player. Then I have sport which belongs to season and seasons has_many :sports.

What I would like is for a player to add a new season(ex. 2011-2012, 2012-2013, 2014-2015 etc) then after the season is created I would like for the player to add the sports they are currently playing that season. I am very confuse at this point because the way I am doing it now forces me to use nested resources that are 3 level deep like so

routes.rb

resources players do 
  resources :seasons do 
    resources :sports
  end
end

If I were to use 3 level deep nested resources I would have to add players to my form that only accepts 2 options.

_form.html.erb

<%= form_for([@season, @sport]) do |f| %>

Would i use a many-to-many association for this or how should I approach this?

score 3 · Accepted Answer · edited May 23 '17 at 12:03

Maybe this will help you clear up some many-to-many questions you have:

Many-to-Many

With your routes, you may not have to nest your routes so deeply... separating may be a better approach.(up to you on how you want your routing)

I see a few many-to-many relationships forming. A player can play many sports, and a perticular sport could have many players. A season can have many different sports, and a sport can have multpile seasons through the years.

Once you have your models figured out, if you want a form that manipulates two different models, you should look into nested_forms

Nested_forms

Hopefully this will help you get started/clear some things up for you!

I too built a sports app(basketball), and ran into some issues with many-to-many relationships and nesting forms here. Maybe you can use this as reference/guide along the way

Rails: When to use many to many assocations?

1 Answers1