Active Record Querying Methods Lab

Learning Goals

Create a table using Active Record
Use Active Record's querying methods

Introduction

In this lab, we'll be working in a TV show domain. We have a TV show model, the Show class, and a shows table that you'll create in your database.

You'll be required not only to write a migration that creates a shows table and gives the Show class certain attributes, but also to use Active Record's querying methods.

Active Record Querying Methods

Active Record makes it easy to ask our database for certain information and datasets by providing a bunch of built-in methods for us. For example, we can request the sum of all of the values of a particular column with the #sum method:

ClassName.sum(:column_name)

We can query our database based on certain conditions using the #where method.

Let's say we have a Song class and table and each song has a number_of_stars rating attribute. We could query for songs with more than 3 stars like this:

Song.where("number_of_stars > ?", 3)

Let's look at one more example: Let's say we want to query our database for the lowest value in the number_of_stars column, i.e., the lowest rating that any song has:

Song.minimum(:number_of_stars)

You'll be writing methods that rely on Active Record methods like #minimum, #sum, and #where to get these tests passing.

Use the following resources to help you find the Active Record query methods that will help you pass these tests:

Instructions

Migration

Create a migration called create_shows using Rake.

In the migration file, write the migration code to create a shows table. The table should have name, network, day, and rating columns. name, network, and day have a datatype of string, and rating has a datatype of integer.

Create a file, show.rb, in app/models. In this file, you will define a Show class that inherits from ActiveRecord::Base.

Oops, we forgot a step in our first migration! Create a second migration to add another column to our shows table. Use Rake to generate a add_season_to_shows migration file. Write a migration to add a column, season, to the shows table. The datatype of this column is string.

Methods

You'll be defining the following methods as class methods on the Show class:

.highest_rating: This method should return the highest value in the ratings column. Hint: if there is a .minimum Active Record method, might there be a .maximum method?
.most_popular_show: Returns the show with the highest rating.
.lowest_rating: Returns the lowest value in the ratings column.
.least_popular_show: Returns the show with the lowest rating.
.ratings_sum: Returns the sum of all of the ratings.
.popular_shows: Returns a list of all of the shows that have a rating greater than 5. Hint: use the .where Active Record method.
.shows_by_alphabetical_order: Returns an array of all of the shows sorted in alphabetical order according to their names. Hint: use the .order Active Record method.

Andrew-Ochieng/phase-3-active-record-querying-methods-lab