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

We have three models: Toy, Purchase, and Kid.

For our purposes, a Toy has many Purchases, a Kid has many Purchases, and a Purchase belongs to a Toy and to an Kid.

Toy - Kid 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.

• Active Record Migrations
• Active Record Associations
• Class and Instance Methods
• Active Record Querying

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 code challenge 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.

Writing error-free code is more important than completing all of the deliverables listed - prioritize writing methods that work over writing more methods that don't work. You should test your code in the console as you write.

Similarly, messy code that works is better than clean code that doesn't. First, prioritize getting things working. Then, if there is time at the end, refactor your code to adhere to best practices.

Before you submit! Save and run your code to verify that it works as you expect. If you have any methods that are not working yet, feel free to leave comments describing your progress.

The starter code has migrations and models for the initial Kid and Toy models, and seed data for some Kids and Toys. The schema currently looks like this:

You will need to create the migration for the purchases table using the attributes specified in the deliverables below.

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 a migration for the purchases table.

• A Purchase belongs to a Toy, and a Purchase also belongs to an Kid. In your migration, create any columns your purchases table will need to establish these relationships.
• The purchases table should also have:
  • A quantity column that stores an integer.

After creating the purchases table using a migration, use the seeds.rb file to create instances of your Purchase class so you can test your code.

Once you've set up your purchases table, 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).

• Purchase#kid
  • should return the Kid instance for this purchase
• Purchase#toy
  • should return the Toy instance for this purchase

• Toy#purchases
  • returns a collection of all the purchases for the toy
• Toy#kids
  • returns a collection of all the kids who performed in the toy

• Kid#purchases
  • should return a collection of all the purchases that the kid has played
• Kid#toys
  • should return a collection of all the toys that the kid has performed in

Use rake console and check that these methods work before proceeding. For example, you should be able to call Kid.first.toys and see a list of the toys for the first kid in the database based on your seed data; and Purchase.first.kid should return the kid for the first purchase in the database.

• Purchase#info
  • should return a string formatted as follows: {insert kid name} bought {insert purchase quantity} {insert toy name} toys.

• Kid#make_purchase(toy, quantity)
  • takes a toy (an instance of the Toy class) and a quantity (string) and creates a new purchase in the database associated with this kid and the toy
• Kid#all_purchase_info
  • should return an Array of strings with all the purchases for this kid formatted as follows: ["{insert kid name} bought {insert purchase quantity} {insert toy name} toys.", ...]
• Kid#throw_out(toy)
  • takes an toy (an instance of the Toy class) and reduces the quantity purchased of that toy by 1
  • you will have to update the quantity column from a row from the purchases table to get this to work!
• Kid#throw_all_out(toy)
  • takes an toy (an instance of the Toy class) and removes their purchase from this kid
  • you will have to delete a row from the purchases table to get this to work!

• Toy.most_expensive
  • returns one instance of a Toy with the highest price
• Toy.most_popular
  • returns one instance of a Toy that has the most purchases (quantity doesn't matter)
• Toy#kids_names
  • returns of an array of the names of the kids who have purchased the toy