Simple Association Issue

rubyonrails-talk
1

Hi There,

Im trying to get my head around a model association issue that I've been struggling with despite the fact that I know I've done the exact same thing previously.

I have the following models:

class User < ActiveRecord::Base

  has_many :user_mailboxes

end

class UserMailbox < ActiveRecord::Base

  belongs_to :user

end

This all works fine and user maps to usermailbox through user_id.

The problem Im having is that the usermailbox table also has a "other_user_id" field which also links back to the users table. I cannot for the life of me figure out how I set this up in the model so that i would be able to call something along the lines of:

for item in @user.user_mailboxes

    item.other_user.first_name

end

So in essence my issue is that I have two fields in one table pointing back at the same table and need to setup associations.

Any help would be greatly appreciated.

Cheers, Chris

2

There was recently a discussion of exactly the same scenario here:

That should answer your question.

3

This all works fine and user maps to usermailbox through user_id.

The problem Im having is that the usermailbox table also has a "other_user_id" field which also links back to the users table. I cannot for the life of me figure out how I set this up in the model so that i would be able to call something along the lines of:

for item in @user.user_mailboxes

   item.other_user.first_name

end

So in essence my issue is that I have two fields in one table pointing back at the same table and need to setup associations.

belongs_to :foo, :class_name => 'Bar' creates an association with Bar usin foo_id as the foreign key

Fred

4

Hi Fred,

So that means in my user model I can associate by using the following?

belongs_to :other_user, :class_name => "UserMailbox"

But what about when I want to go back the other way? So I have the mailbox object which has the field "other_user_id" but how do I create the association between this ID and the ID in the users table which is its primary key (id)?

Chris

5

Hi Fred,

Please quote the previous message so that the thread is easier to follow.

So that means in my user model I can associate by using the following?

belongs_to :other_user, :class_name => "UserMailbox"

But what about when I want to go back the other way? So I have the mailbox object which has the field "other_user_id" but how do I create the association between this ID and the ID in the users table which is its primary key (id)?

Did you read through the thread referenced by Robert? Did you work right through and understand everything there? (Particularly note the use of foreign_key).

Colin

6

Sure did:

class User < ActiveRecord::Base

  has_many :user_mailboxes   belongs_to :other_user, :class_name => "UserMailbox" end

class UserMailbox < ActiveRecord::Base

  belongs_to :user   belongs_to :other_user, :class_name => "User" end

Very helpful guys,

Thanks, Chris

7

Sure did:

Sure did what? Please quote the previous post so each message makes sense.

class User < ActiveRecord::Base

has_many :user_mailboxes belongs_to :other_user, :class_name => "UserMailbox"

That does not look right.

end

class UserMailbox < ActiveRecord::Base

belongs_to :user belongs_to :other_user, :class_name => "User"

Where is the has_many or has_one at the other end of this?

Colin