CODEWITHSUNDEEP
ruby-on-railsdatabase-designactiverecordforeign-key-relationship
pablomarti
pablomarti

Reputation: 2107

Problems with 2 relationships between 2 tables in the same column under Ruby on Rails

I have a doubt, Im making a friend's platform on a Ruby on Rails site; I have a table called users, and a table called friends that manages the friendships between the users. In friends I have 2 fields, *user_id1* and *user_id2*. This is the relationship I made in the models:

class User < ActiveRecord::Base
    has_many :friends
end

class Friend < ActiveRecord::Base
    belongs_to :user, :foreign_key => "user_id1"
    belongs_to :user, :foreign_key => "user_id2"
end

Is this a good way to handle this situation? Another idea is create another model that points to the same table in the database, userAux, and use it for the relationship. What do you think is best? Do you have a better idea?

Thanks in advance.

Upvotes: 0

Views: 360

Answers (2)

PerformanceDBA
PerformanceDBA

Reputation: 33698

A self-referencing many-to-many structure is often called a Bill of Materials. It is a very good idea, and quite commonly used in Relational databases. Here is the Data Model. You would have boolean attributes such as IsAccepted and IsRejected.

Please do not name the columns as user_id1, 2. Please call them something that is actually meaningful, such host_id and guest_id or requester_id and friend_id. The relevance of that will only become clear when you are coding.

Readers who are unfamiliar with the Relational Modelling Standard may find IDEFIX Notation useful.

Upvotes: 4

Sean Hill
Sean Hill

Reputation: 15056

There is actually a very similar situation referenced here: http://oldwiki.rubyonrails.org/rails/pages/HowToCreateASelfReferentialManyToManyRelationship

Upvotes: 1

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