A User to User Relationship

rubyonrails-talk
1

You'll need a many-many relationship with User to itself. You use two tables for this kind of relationship:

- users and - user_user

user_user has no id column, but does have user_one_id and user_two_id columns. It's basically a map of friends:

user id=1 is friends with user id=2 user id=1 is friends with user id=3 user id=2 is friends with user id=4

etc.

Just as you wuold use 'belongs to' and 'has many' in your model, you use:

   has_and_belongs_to_many :users, :join_table => "user_user"

Rails should then give you nice friendly access to your friends. You don't even need to define a single reference in the user table! I haven't used it myself yet, but I believe you'll get access to the friends as an array :-

my_user = User.find(:first) my_user.users

(I may be wrong!)

Ben

2

I have done a similar thing, and I created a friendship model for this.

The main reason is that in my system a friendship goes through multiple stages. One user initiates a friendship request or invite, and the other user either accepts (establishes a friendship) or rejects the offer. Then at any time, one user might terminate the friendship. I feel there is enough information here to warrant another model, and a few columns in the friendship table.

I always query this model from the perspective of the active user (I provide the user_id as a query condition), which avoids having to deal with queries that include the user table twice. Then again, I'm kind of a newbie, and maybe avoiding the problem is not your preference. :slight_smile:

I don't have my code on me, but I hope this is a little helpful.

Chris