Movie Buff

For this project you will be writing Active Record queries against the actors, movies, and castings tables from the SQL Zoo project. RSpec tests will check that you both return the correct results and query the database the specified number of times. Please run them to check your work.

It may be helpful to refer to the SQL Zoo exercises for guidance as you work through these problems. Also make sure to reference the past Active Record readings as well as the Active Record docs.

Learning goals

By the end of this project you should be able to

Use Active Record's various querying methods
Write complex, chained Active Record queries
Test and debug Active Record queries

Setup

First, make sure Postgres is running:

Mac: You should see an elephant icon in your menu bar; if you don't, start Postgres.app (it's in Applications). Click the icon. If you see a green checkmark in the dropdown menu, you're good; if not, click the Start button.
Windows (WSL) / Ubuntu: Run sudo service postgresql start in your terminal.

Then clone the skeleton repo from the Download Project link at the bottom of this page. Run bundle install and ./setup to populate the database. (If you get a permission error, run chmod +x setup and then ./setup again.)

Run bundle exec rspec to test.

If you'd like to run specs for a particular problem, simply append the corresponding line number to the spec file you want to run, like so:

bundle exec rspec spec/01_queries_spec.rb:66

You'll be working in the movie_buff folder. Do the problems in 01_queries.rb before moving on to 02_queries.rb and then 03_queries.rb. Information on the tables you will be working with can be found below:

# == Schema Information
#
# Table name: actors
#
#  id         :bigint           not null, primary key
#  name       :string           not null
#  created_at :datetime         not null
#  updated_at :datetime         not null
#
# Table name: movies
#
#  id          :bigint           not null, primary key
#  title       :string           not null
#  yr          :integer          not null
#  score       :float            not null
#  votes       :integer          not null
#  director_id :bigint           
#  created_at  :datetime         not null
#  updated_at  :datetime         not null
#
# Table name: castings
#
#  id         :bigint           not null, primary key
#  actor_id   :bigint           not null
#  movie_id   :bigint           not null
#  ord        :integer          not null
#  created_at :datetime         not null
#  updated_at :datetime         not null

Notes on building Active Record queries

You can manually test queries in the rails console. Remember that appending to_sql--which returns the SQL query Active Record makes under the hood--or as_json--which converts a query's output into a regular Hash--to the end of a query can help with debugging. See last night's "Movie Buff in Training" homework for tips on how to use these two methods.

Also remember that Active Record can joins on a model's associations. The models in the skeleton repo already have associations defined for actors, castings, and movies. Please take a look at these associations before you begin.

Have fun and good luck!

LandoMeowrissian/W5D5

Movie Buff

Learning goals

Setup

Notes on building Active Record queries