For this assignment, we'll be working with a hospital domain.

IGNORE THIS SECTION UNTIL YOU GET TO STAGE 2 (going over AR Associations material) We have four models: Patient, Doctor, Prescription

For our purposes, a Patient can has many Prescriptions. A Doctor can has many Prescriptions. A Prescription belongs to a Patient and a prescribing Doctor. Patient - Doctor is a many to many relationship.

Note: You should draw your domain on paper or on a whiteboard before you start coding. Remember to identify a single source of truth for your data. END OF THE SECTION

Stage 1 (Complete before learning Active Record Associations)

• Active record migrations
• Write class and instance methods using Active Record
• Use Active Record to query the database

Stage 2 (Complete only after you learn Active Record Associations)

• Everything from Stage 1 plus,
• Write Active Record associations
• Write class and instance methods that rely on Active Record Associations

To get started, run bundle install while inside of this directory.

Build out all of the methods listed in the deliverables. The methods are listed in a suggested order, but you can feel free to tackle the ones you think are easiest. Be careful: some of the later methods rely on earlier ones.

Remember! This exercise does not have tests. You cannot run rspec and you cannot run learn. You'll need to create your own sample instances so that you can try out your code on your own. Make sure your associations and methods work in the console before submitting.

We've provided you with a tool that you can use to test your code. To use it, run rake console from the command line. This will start a pry session with your classes defined. You can test out the methods that you write here. You are also encouraged to use the seeds.rb file to create sample data to test your models and associations.

Write the following methods in the classes in the files provided. Feel free to build out any helper methods if needed.

Deliverables use the notation # for instance methods, and . for class methods.

Remember: Active Record give your classes access to a lot of methods already! Keep in mind what methods Active Record gives you access to on each of your classes when you're approaching the deliverables below.

Before working on the rest of the deliverables, you will need to create migrations for all the tables.

• A Patient has a first name, last name, DOB, gender ('F', 'M'), address and phone number.
• A Doctor has a first name, last name, DOB, address, phone number and a salary.
• An Prescription belongs to a Patient and to an attending Doctor (create any columns will need to establish these relationships using the right foreign keys) and also has:
  • a description and a total_cost columns. Note: the description should be the name of the medicine (i.e. Vicodin, Metformin, Advil, etc.)

After creating the tables using migrations, use the seeds.rb file to create instances of your three classes so you can test your code.

Once you've set up your tables, work on building out the following deliverables.

Use Active Record association macros and Active Record query methods where appropriate (i.e. has_many, has_many through, and belongs_to).

• Prescription#patient
  • returns the Patient instance for this prescription
• Prescription#doctor
  • returns the Doctor instance for this prescription

• Patient#prescriptions
  • returns a collection of all the prescriptions that the Patient has been prescribed

• Doctor#prescriptions
  • returns a collection of all the prescriptions that the Doctor has prescribed

Use rake console and check that these methods work before proceeding. For example, you should be able to call Doctor.first.prescriptions and see a list of the appointments for the first doctor in the database based on your seed data; and Prescriptions.first.doctor should return the doctor for the first prescription in the database.

• Patient#print_patient_info (Stage 1)

  • should return a string formatted as follows: Patient: {patient full name} DOB: {patient DOB} Address: {patient address}

• Patient#update_address(new_address) (Stage 1)

  • should update the address for the patient.

• Patient#received_medicine?(medicine_name) (Stage 2)

  • accepts an medicine_name (string) and returns true if any of the prescriptions associated with the patient has that medicine_name, otherwise returns false

• Patient#average_cost (Stage 2)

  • returns a float representing the average cost for all prescriptions for this patient.

• Doctor#write_prescription(patient, date, description, total_cost) (Stage 1)

  • takes a patient (an instance of the Patient class), a description and a total_cost as arguments, and creates a new Prescription instance associated with this doctor and the given patient.

• Doctor.lowest_salary (Stage 1)

  • returns the lowest salary among doctors.

• Doctor.doctor_lowest_salary (Stage 2)

  • returns the Doctor instance with the lowest salary.

• Doctor.over_300K (Stage 2)

  • returns the number of doctors that have salaries over 300K formatted as follows: There are currently {insert the count here} doctor(s) earning more than 300K

• Doctor#remove_prescriptions(patient) (Stage 2)

  • takes a Patient instance and remove all prescriptions for that patient that were prescribed by this doctor

• Prescription.cost_over_500 (Stage 1)

  • returns the prescriptions with total cost greater than $500

• Prescription.were_prescribed_by_gender(medicine_name, gender) (Stage 2)

  • accepts a medicine_name and a gender and returns an array of all Patient instances of the given gender that were prescribed that medicine.