Rails Data Modelling: How can I model a has_many relationship that's actually a collection of another model?

Question

To be more specific, I have a User model that has_one Profile, now I'm in the need to add a has_many relationship from User to a new model Contact, but Contact is really a collection of Profiles ("User has_many Profiles" behind the scenes).

How do I correctly model this? Is there a way to avoid creating the new Model Contact altogether?

My concern, and reason to ask this question is having to perform an inefficient query to retrieve the User Contacts collection: user.contacts and then for each Contact I'd have to create a Query to retrieve each Profile, right?

How I can make it so that when I do: user.contacts it retrieves a Collection of Profiles that Doesn't interfere/is independent of the user.profile relationship?

Thanks in advance!

Answer 1

You wouldn't be necessarily need a new Model, but it's easiest (at least, in my opinion) to have one, just not in the way presented above.

Rails aside, you need a join table, like user_profiles, which contains foreign keys for user_id and profile_id. Now, how you make that work is up to you.

Your Contact model here is actually, in a more Rails-y way, a UserProfile model. So your User could look like:

class User
  has_many :user_profiles # the join table
  has_many :contacts, through: :user_profiles

  has_one: profile
end

Here, user.contacts would get you the profiles. You still have that extra model, UserProfile, you just don't use it in practice:

class UserProfile
  belongs_to :user
  belongs_to :profile
end

Which you can build via:

rails g model UserProfile user:references profile:references

Hope that helps!