CODEWITHSUNDEEP
ruby-on-railsdatabase-designmodel
Hommer Smith
Hommer Smith

Reputation: 27852

How to organize seasons in Clubs and Teams for Rails models?

I have the following situation:

I have a Club which can have several Teams, and a Team can have several Players.

However, the Players that a Team has will vary each year. I am wondering how could I put somehow season information into the picture in a way that the user will be able to add/remove Players each season and be able to see Players of a team from previous seasons.

So, given the following models:

Club has_many Team
Team belongs_to Club
Team has_many Players

How would I make it so that Team has_many Players depends on the Season (2013/2014 - 2012/2013..)

Upvotes: 0

Views: 469

Answers (2)

Panickos Neophytou
Panickos Neophytou

Reputation: 525

There are two ways to do it:

One is to create another relation for the SEASON and create a ternary relationship (http://www.databasedesign.co.uk/bookdatabasesafirstcourse/chap3/chap3.htm)

Ternary relationship

The tables would look something like this:

    PLAYER(id,...)
    TEAM(id,name,...,club_id)
    SEASON(id,season_name,...)
    SEASON_PARTICIPATION(id,player_id,season_id,team_id)

And the ActiveRecord associations would be:

    class Club < ActiveRecord::Base
      has_many :teams
    end

    class Team < ActiveRecord::Base
      belongs_to :club
      has_many :players, through: :season_participations
    end

    class Player < ActiveRecord::Base
      belongs_to :teams, through: :season_participations
    end

    class Season < ActiveRecord::Base
      has_many :players, through: :season_participations
    end

    class SeasonParticipation < ActiveRecord::Base
      belongs_to :player
      belongs_to :team
      belongs_to :season
    end

More documentation on ActiveRecord associations can be found here: http://guides.rubyonrails.org/association_basics.html#the-has-many-through-association

Another way of doing this is to skip the SEASON relation all together and have it as a simple attribute in the SEASON_PARTICIPATION relation. So instead of a season_id you would have the name of the season in the SEASON_PARTICIPATION (see diagram 2). Having a separate SEASON relation gives you the opportunity to store more information about the season, like start-date/end-date etc. Eventually you could also add division information in another relation.

No ternary relation

Upvotes: 4

FCStrike
FCStrike

Reputation: 365

There's many ways you could do this. Here's a few that spring immediately to mind.

  1. Add a season column to the Player model. Have the Player's season attribute be set on create via callback. If the season != current_season, prevent the user from creating, updating, or destroying the player.
  2. Use the updated_at column which is already provided in the Player model to do basically the same thing. Create a method which parses the datetime and converts it into something more useful to you, probably a season number or something along those lines.

Upvotes: 0

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