Phase 3 Active Record Mock Code Challenge: Game Reviews
For this assignment, we'll be working with a video games domain.
We're building a site that will allow a user to write reviews about video games (and to add games to a favorites list (ADVANCED)).
We are given three models: User
, Game
, and Category
Core Deliverables
For the purposes of the core deliverables, a User
can write reviews for many Game
s and a Game
can receive reviews from many User
s.
User
- Game
is a many to many relationship.
Category
- Game
is a one to many relationship.
You will need more relationships. What are they?
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.
Note: This mock code challenge is more challenging than the actual code challenge, especially with the advanced deliverables.
Topics
- Active Record Migrations
- Active Record Associations
- Class and Instance Methods
- Active Record Querying
Instructions
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.
What You Already Have
The starter code has migrations and models for the initial User
, Game
and Category
models, and seed data for some User
s, Game
s and Category
(ies). The schema currently looks
like this:
users Table
Column | Type |
---|---|
username | String |
String |
games Table
Column | Type |
---|---|
name | String |
platform | String |
categories Table
Column | Type |
---|---|
name | String |
You will need to create migrations for additional tables using the attributes specified in the deliverables below.
Deliverables
Write the following methods in the classes in the files provided or additional model classes you need to create. 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.
Migrations
Before working on the rest of the deliverables, you will need to create more
migrations. Let's start with a migration for the review
table.
- A
Review
belongs to aUser
, and aReveiw
also belongs to aGame
. In your migration, create any columns yourreviews
table will need to establish these relationships using the right foreign keys. - The
reviews
table should also have:- A
content
column that stores a string. - A
rating
column that stores an integer (1-5).
- A
After creating the reviews
table using a migration, use the seeds.rb
file to
create instances of your Review
class so you can test your code.
Once you've set up your tables, work on building out the following deliverables.
Object Association Methods
Use Active Record association macros and Active Record query methods where
appropriate (i.e. has_many
, has_many through
, and belongs_to
).
Review
Review#user
- returns the
User
instance for this Review
- returns the
Review#game
- returns the
Game
instance for this Review
- returns the
User
User#reviews
- returns a collection of all the reviews for the User
User#games
- returns a collection of all the games reviewed by the User
Game
Game#users
- returns a collection of all users who have reviewed the Game
Game#reviews
- returns a collection of all the reviews of that Game
Category
Category#games
- returns a collection of all the games that belong to a given category
Use rake console
and check that these methods work before proceeding. For
example, you should be able to call User.first.games
and see a list of the
games reviewed by the first user in the database based on your seed data; and
Review.first.user
should return the user for the first review in the database.
Aggregate and Association Methods
Review
Review#print_details
- should return a string formatted as follows:
{insert user's name} gives {insert games's name} {insert review's rating} stars: {insert review's content}
- should return a string formatted as follows:
User
User#write_review(game, content, rating)
- takes a
game
(an instance of theGame
class), somecontent
(string), and arating
integer as arguments, and creates a newReview
instance associated with this User and the given Game
- takes a
User.most_reviews
- returns the
User
instance with the most reviews associated with it
- returns the
Game
Game#average_rating
- returns the average ratings from a game's reviews as a float, or the string 'No ratings yet'
Game.find_by_platform(platform)
- accepts a platform string and returns a collection of
Game
instances that are for that platform
- accepts a platform string and returns a collection of
Category
Category#platforms
- returns a collection (strings) of the platforms available for a given category without duplicate strings
Category.highest_rated
- returns a category instance connected to the game with the highest current rating
- (for Advanced Deliverables, we'll have to allow this method to return an array of categories)
Advanced deliverables
Only attempt these when you have completed and tested the deliverables above. Be sure you have made a commit of the working code before starting on advanced deliverables.
We're going to expand on our model associations now.
A User
can favorite many Game
s and a Game
can be favorited by many User
s. A Game
can have many Category
(ies) and a Category
can have many Game
s.
What other table or tables will you need to create so that users can favorite many games and games can have multiple categories? Review the relationships just described and update your Entity Relationship Diagram (ERD). Do you need to update anything in the existing code to make this work?
Object Association Methods
User
User#favorite_games
- returns a collection of all the games favorited by the User
- (at this point, you may run into an issue you haven't encountered up until now: how in the world can you define more than one
has_many, through:
association that join the same two models through different join models? You'll want to look into association aliases and focus on the syntax around using a custom name for ahas_many through:
association)
Game
Game#favoriters
- returns a collection of all the users who have favorited that Game
- (see the above on how to alias your associations)
Game#categories
- returns a collection of the game's categories
Aggregate and Association Methods
User
User#add_favorite(game)
- takes a
game
(an instance of theGame
class), as an argument, and creates the proper association between this user instance and the givengame
- takes a
Game
Game#add_category(category)
- accepts a
category
(instance) and associates it with the game instance it's called on
- accepts a
Game.most_popular
- returns the game instance that has been favorited by the most users
Category
Category.most_popular
- returns an array of categories based on the current most-popular game