Book Image

The Ruby Workshop

By : Akshat Paul, Peter Philips, Dániel Szabó, Cheyne Wallace
Book Image

The Ruby Workshop

By: Akshat Paul, Peter Philips, Dániel Szabó, Cheyne Wallace

Overview of this book

The beauty of Ruby is its readability and expressiveness. Ruby hides away a lot of the complexity of programming, allowing you to work quickly and 'do more' with fewer lines of code. This makes it a great programming language for beginners, but learning any new skill can still be a daunting task. If you want to learn to code using Ruby, but don't know where to start, The Ruby Workshop will help you cut through the noise and make sense of this fun, flexible language. You'll start by writing and running simple code snippets and Ruby source code files. After learning about strings, numbers, and booleans, you'll see how to store collections of objects with arrays and hashes. You'll then learn how to control the flow of a Ruby program using boolean logic. The book then delves into OOP and explains inheritance, encapsulation, and polymorphism. Gradually, you'll build your knowledge of advanced concepts by learning how to interact with external APIs, before finally exploring the most popular Ruby framework ? Ruby on Rails ? and using it for web development. Throughout this book, you'll work on a series of realistic projects, including simple games, a voting application, and an online blog. By the end of this Ruby book, you'll have the knowledge, skills and confidence to creatively tackle your own ambitious projects with Ruby.
Table of Contents (14 chapters)

Associations

In the previous chapter, we created a review web application where only authenticated users were allowed to write reviews. Ideally, every review would always allow other users to comment on it, and in this section, we will build that feature.

This means we will create a new model called Comment, which will be associated with the Review model since every review could have many comments, while every comment belongs to one review only. This is called a one-to-many relationship between the two models.

Associations are a set of methods for connecting objects of different models using foreign keys. Associations make it really simple to interact and perform various operations with records using Ruby code.

The following are six types of associations provided by Rails:

  • belongs_to
  • has_one
  • has_many
  • has_many :through
  • has_one :through
  • has_and_belongs_to_many

Let's discuss them one by one.

belongs_to

In the belongs_to association...