I am building a daily deal app to better learn Ruby on Rails.
On M. Hartly tutorial, I understood the concept of models and their relationship (a microposts belongs_to a user, and a user has_many microposts).
However I am not sure how to put that into practice on my daily deal project.
I decided to have a Model for users with two type of users with different rights:
Both users go into the users database
I also decided to have a model for deals and go in the Deals database
So have I understood well:
a admin_user has_many deals
deals belongs to a admin_user
standard_user has many deals (indeed he can participate in many deals)
and deals do NOT belong to standard_user so I can’t say anything here.
Have I understood things right? It is possible to define according to the type of right of a user different relationship to a model object(in this case: deals)
PS: I think I’ll separate users with cancan gem to give them different rights
The biggest issue with what you're describing is that a standard_user has_many :deals, but deals don't belong to a standard_user; they probably are in use by many standard users at the same time. That means that a deal can't belong_to a standard_user, because you can't have a standard_user_id column in your Deals table (since you'd need arbitrarily many columns to deal with the arbitrarily many users who might participate).
In order to have a many-to-many relationship like this, you need a link table. Here's one way to achieve this in Rails:
class DealParticipation < ActiveRecord:Base
#This means the deal_participations table has a standard_user_id key
belongs_to :standard_user
#This means the deal_participations table has a deal_id key
belongs_to :deal
#... more logic goes here ...
end
Now your standard user looks like:
class StandardUser < ActiveRecord::Base
has_many :deal_participations
has_many :deals, :through => :deal_participations
# ... more logic goes here ...
end
And your deal class looks like:
class Deal < ActiveRecord::Base
has_many :deal_participations
has_many :standard_users, :through => :deal_participations
belongs_to :admin_user
#... more logic goes here ...
end
You'll then need three tables: one for deals, one for deal_participations, and one for standard_users (plus the stuff for admin users).
Depending on your needs, you may also want to try using single-table inheritance (STI) to make Users and Admin Users derive from a common base class. You can read more about STI here.
I hope that helps! Enjoy getting started with Rails!
Assuming that each deal is associated with a single admin_user, then I think you're first three bullets are correct. With respect to your fourth bullet, however, you could use has_many :through or has_and_belongs_to_many to model the relationship between standard_user and deal as discussed in this Rails guide. In the latter case, standard_user's has_many relationship to deal would change to has_and_belongs_to_many.
As for using User subclasses to define relationships, yes, you can do this, but see http://guides.rubyonrails.org/association_basics.html for a general discussion of this approach.
Pete
