How to group multiple models under the same name in unidirectional inheritance classes

Question

(See below for a link to a sample project)

WHAT I WORK:

I have many types of users that I work with using Single Table Inheritance in Rails, for example:

class User < ActiveRecord::Base self.inheritance_column = :meta_type scope :doctors, -> { where(meta_type: 'Doctor') } scope :patients, -> { where(meta_type: 'Patient') } scope :nurses, -> { where(meta_type: 'Nurse') } scope :employees, -> { where(meta_type: 'Employee') } end class Doctor < User has_many :doctor_patient_relations has_many :patients, :through => :doctor_patient_relations has_many :doctor_nurse_relations has_many :nurses, :through => :doctor_nurse_relations ... # More join tables between each type of user end class Patient < User has_many :doctor_patient_relations has_many :doctors, :through => :doctor_patient_relations has_many :nurse_patient_relations has_many :nurses, :through => :nurse_patient_relations has_many :employee_patient_relations has_many :employees, :through => :employee_patient_relations end 

In total, I have 4 User types: Doctor , Nurse , Employee and Patient .

What I want to do is get all the doctors, nurses and patient staff with this call:

 @this_patient.providers # => [doctor1, nurse2, employee3] 

To achieve this, I thought about deleting 3 different types of connection tables between the patient and the provider (e.g. doctor_patient_relations) and replacing them with a whole single table called provider_patient_relations.

NEW FILE, I SHOULD TRY TO GET THIS WORK:

 class ProviderPatientRelation < ActiveRecord::Base belongs_to :provider, class_name: "User", :foreign_key => :provider_id belongs_to :patient, class_name: "User", :foreign_key => :patient_id end 

and I also added this to the User.rb file:

 class User < ActiveRecord::Base ... has_many :provider_patient_relations has_many :patients, -> { where meta_type: 'Doctor' || 'Nurse' }, :through => :provider_patient_relations, :inverse_of => :patient has_many :providers, -> { where meta_type: 'Patient' }, :through => :provider_patient_relations, :inverse_of => :provider end 

The problem is that I do not have a class name provider, rails throws an error:

 NoMethodError: undefined method `_reflect_on_association' for Provider:Class 

How to scan rails for viewing in Doctors, Nurses, and Employees if I call @this_patient.providers ?

EDIT

I have a sample project for work, read the instructions for reading and configure it:

https://github.com/waleedasif322/group-user-types-example-rails

Answer 1

You were very close. In your Patient model, you used “like,” as if you were trying to designate it as an alias. However, the “how” is used for polymorphic associations ... I replaced your Patient model with the following and was able to successfully call Patient.first.providers in the console.

 class Patient < User has_many :patient_provider_relations has_many :providers, through: :patient_provider_relations, source_type: "User" end 

Then I moved the patient service provider partner associations to concern:

 module Patientable extend ActiveSupport::Concern included do belongs_to :provider, polymorphic: true has_many :patient_provider_relations, as: :provider has_many :patients, through: :patient_provider_relations, source: :patient end end 

And finally added include Patientable in your Doctor, Nurse, and Employee models.