Help with active record relations
- by Christian Fazzini
class CreateActivities < ActiveRecord::Migration
def self.up
create_table :activities do |t|
t.references :user
t.references :media
t.integer :artist_id
t.string :type
t.timestamps
end
end
def self.down
drop_table :activities
end
end
class Fan < Activity
belongs_to :user, :counter_cache => true
end
class Activity < ActiveRecord::Base
belongs_to :user
belongs_to :media
belongs_to :artist, :class_name => 'User', :foreign_key => 'artist_id'
end
class User < ActiveRecord::Base
has_many :activities
has_many :fans
end
I tried changing my activity model too, without any success:
class Activity < ActiveRecord::Base
has_many :activities, :class_name => 'User', :foreign_key => 'user_id'
has_many :activities, :class_name => 'User', :foreign_key => 'artist_id'
end
One thing to note. Activity is an STI. Fan inherits from Activity.
In console, I do:
# Create a fan object. User is a fan of himself
fan = Fan.new
=> #<Fan id: nil, user_id: nil, media_id: nil, artist_id: nil, type: "Fan", comment: nil, created_at: nil, updated_at: nil>
# Assign a user object
fan.user = User.first
=> #<User id: 1, genre_id: 1, country_id: 1, ....
# Assign an artist object
fan.artist_id = User.first.id
=> 1
# Save the fan object
fan.save!
=> true
Activity.last
=> #<Fan id: 13, user_id: 1, media_id: nil, artist_id: 1, type: "Fan", comment: nil, created_at: "2010-12-30 08:41:25", updated_at: "2010-12-30 08:41:25">
Activity.last.user
=> #<User id: 1, genre_id: 1, country_id: 1, .....
But...
Activity.last.artist
=> nil
Why is Activity.last.artist returning nil?
