I have the following models:
class Business < ActiveRecord::Base
has_many :customers, :inverse_of => :business
has_many :payments, :inverse_of => :business
end
class Customer < ActiveRecord::Base
belongs_to :business, :inverse_of => :customer
has_many :payments, :inverse_of => :customer
end
class Payment < ActiveRecord::Base
belongs_to :customer, :inverse_of => :payment
belongs_to :business, :inverse_of => :payment
end
Doing business.customers works fine. However, when I do business.payments I get an error: Could not find the inverse association for business (:payment in Business).
I'm not sure why though. I have the same exact associations both ways. My schema.db also looks fine. What could be the issue here?
EDIT
When I remove the inverse_of => :business for has_many :payments, it works. Why does this happen? Is it related to that Payment belongs to customer and business (it shouldn't really matter, right?)?
Update Payment model with this:
class Payment < ActiveRecord::Base
belongs_to :customer, :inverse_of => :payments
belongs_to :business, :inverse_of => :payments
end
you declared
has_many :payments, :inverse_of => :business in Business model
but in Payment you used belongs_to :business, :inverse_of => :payment
it should be belongs_to :business, :inverse_of => :payments
Your problem is at:
belongs_to :business, :inverse_of => :customer
and at:
belongs_to :customer, :inverse_of => :payment
belongs_to :business, :inverse_of => :payment
The other side of belongs_to is has_many, which defines a plural relation. That means the inverse_of should be customers instead of customer and payments instead of payment.
Related
I am trying to transform my HABTM to has_many through relations. Sometimes I have to connect the same models in different ways. For example to specify different roles for authors.
With a HABTM I would do this through the declaration of a class_name option. Just like:-
class Project < ActiveRecord::Base
has_and_belongs_to_many :curators, :class_name => :author, :through => :projects_curators
end
class ProjectsCurator < ActiveRecord::Base
attr_accessible :project_id, :author_id
belongs_to :project
belongs_to :author
end
class Author < ActiveRecord::Base
has_and_belongs_to_many :projects, :through => :projects_curators
end
But when I transform everything into a has_many through:
class Project < ActiveRecord::Base
has_many :project_curators
has_many :curators, :class_name => :author, :through => :project_curators
end
class ProjectCurator < ActiveRecord::Base
attr_accessible :project_id, :author_id
belongs_to :project
belongs_to :author
end
class Author < ActiveRecord::Base
has_many :project_curators
has_many :projects, :through => :project_curators
end
I get: Could not find the source association(s) :curator or :curators in model ProjectCurator. Try 'has_many :curators, :through => :project_curators, :source => <name>'. Is it one of :author or :project?
When I add :source
has_many :curators, :class_name => :author, :through => :project_curators, :source => :author
I get:
uninitialized constant Project::author
How can I get this working? Thank you very much in advance!
Understanding :source option of has_one/has_many through of Rails should help you out
When you declare the source you're not declaring the class of the has_many relationship, but the name of the relationship you're using as the middle man. In your case, try:
has_many :curators, :through => :project_curators, :source => :author
As someone in the above post states:
Most simple answer - the name of the relationship in the middle
I have a User model, a Listing model and an Order model. A user can either place an order or publish a listing which others can place an order for. Thus, a User can be customer as well as supplier.
My Order model has listing_id, from_id and to_id.
My question is, how can I set up associations between these models ? I read the rails guide on associations but the example there were dealing with separate customer and supplier models.
class User < ActiveRecord::Base
has_many :listings, :foreign_key => :supplier_id, :inverse_of => :supplier
has_many :orders, :foreign_key => :customer_id, :inverse_of => :customer
end
class Listing < ActiveRecord::Base
belongs_to :supplier, :class_name => 'User'
belongs_to :order
end
class Order < ActiveRecord::Base
belongs_to :customer, :class_name => 'User'
has_many :listings
end
My db schema:
tournaments(id, ...)
teams(tournament_id, id, ...)
matches(tournament_id, id, team_id_home, team_id_away, ...)
Models:
class Tournament < ActiveRecord::Base
has_many :teams, dependent: :destroy
has_many :matches, dependent: :destroy
...
end
class Team < ActiveRecord::Base
belongs_to :tournament
...
end
class Match < ActiveRecord::Base
belongs_to :tournament
has_many :teams
...
end
I would like to have the following data in my view:
match_id team_id_home team_id_away team_id_home_name team_id_away_name
So, I'm asking for help with the following query (I'm trying to get team's names, but having problem with joining):
#matches = #tournament.matches.where(:tournament => #tournament).joins(:teams).paginate(page: params[:page])
I'm fairly new to rails, but you should be able to setup your associations like this: (going from memory)
class Match < ActiveRecord::Base
belongs_to :tournament
has_one :home_team, :class_name => "Team", :foreign_key => "team_id_home"
has_one :away_team, :class_name => "Team", :foreign_key => "team_id_away"
end
#####
m = Match.first
m.away_team.team_name
m.home_tam.team_name
Or in your case:
#matches = #tournament.matches.paginate(page: params[:page])
I don't think you need the where function: the has_many association tells rails to only pull matching matches.
It is belongs_to, not has_one in Match model.
class Match < ActiveRecord::Base
belongs_to :tournament
belongs_to :home_team, :class_name => "Team", :foreign_key => "team_id_home"
belongs_to :away_team, :class_name => "Team", :foreign_key => "team_id_away"
end
class Team < ActiveRecord::Base
belongs_to :tournament
has_many :matches
end
Now I can use tournament.home_team.name in my view
I'm currently modeling a Rails 3.2 app and I need a polymorphic association named "archivable" in a table named "archives". No worries with it, but my "archives" table must also belongs_to a "connections" table. I just want to know if there's any constraints from Rails to do that.
You can see the model here
Another detail, my Connection model has twice user_id as foreign key. A user_id as sender and a user_is as receiver. Possible? I think what I did below won't work...
Here are my models associations.
class User < ActiveRecord::Base
has_many :connections, :foreign_key => :sender
has_many :connections, :foreign_key => :receiver
end
class Connections < ActiveRecord::Base
belongs_to :user
has_many :archives
end
class Archive < ActiveRecord::Base
belongs_to :connection
belongs_to :archivable, :polymorphic => true
end
class Wink < ActiveRecord::Base
has_many :archives, :as => :archivable
end
class Game < ActiveRecord::Base
has_many :archives, :as => :archivable
end
class Message < ActiveRecord::Base
has_many :archives, :as => :archivable
end
Do you see anything wrong or something not doable with Rails?
Thank you guys.
I think you want to do this :
class Connections
belongs_to :sender, :class_name => 'User', :foreign_key => 'sender_id'
belongs_to :receiver, :class_name => 'User', :foreign_key => 'receiver_id'
end
class User
has_many :sended_connections, :class_name => 'Connection', :as => :sender
has_many :received_connections, :class_name => 'Connection', :as => :receiver
end
Important : Don't declare 2 times has_many :connections with the same name !
i have the following models
class Airplane < ActiveRecord::Base
has_many :airtags
has_many :pictures, :through => :airtags
end
class Airtag < ActiveRecord::Base
attr_accessible :airable_type, :airable_id, :airplane_id
belongs_to :airplane
belongs_to :airable, :polymorphic => true
end
class Picture < ActiveRecord::Base
belongs_to :picturable, :polymorphic => true
has_many :airtags, :as => :airable, :dependent => :destroy
has_many :airplanes, :through => :airtags
end
in my airplane show, i want to list all pictures, ordered by their name.
#airplane.pictures.order(:name)