CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-4activerecordhas-many-throughhas-many
NothingToSeeHere
NothingToSeeHere

Reputation: 2363

querying current and previous relationships using has_many through: in Rails

I have a project management app that has 3 models…Project, Users, and Participation. I would like to be able to show a list of all the Users who have collaborated with a given User on any of the Projects the Given User was a Participant in. This includes past Projects.

For Instance UserA & UserB were in ProjectBlue UserA & UserC were in ProjectYellow UserA & UserC & UserD were in ProjectRed

If I am in UserA’s dashboard I want to be able to see a list that says:

"You’ve worked with: UserC(only listed once) UserD UserB”

Do I need to create a whole :relationships Table with a :user_id, :project_id, record for EVERY shared connection? This doesn’t seem efficient.

Models

Class Project < ActiveRecord::Base
  belongs_to :user # (this is the organizer)
  has_many :users, through: :participants
  has_many :participants

Class User < ActiveRecord::Base 
  has_many :projects
  has_many :project, through :participant
  has_many :participants

Class Participant < ActiveRecord::Base
  belongs_to :project
  belongs_to :user

Upvotes: 1

Views: 61

Answers (1)

wintermeyer
wintermeyer

Reputation: 8318

That is the correct way. Database space is free and the database is bored anyway. It'll appreciate some data to work with. ;-)

Have a look at http://www.xyzpub.com/en/ruby-on-rails/4.0/ar-many_to_many.html for some examples.

But I'm not sure about your models. They do seem to be a bit strange. You probably want:

Class Project < ActiveRecord::Base
  belongs_to :user # (this is the organizer)
  has_many :participants
  has_many :users, through: :participants

Class User < ActiveRecord::Base 
  has_many :participants
  has_many :projects, through: :participants

Class Participant < ActiveRecord::Base
  belongs_to :project
  belongs_to :user

Upvotes: 1

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