Acing the Ruby on Rails Developer Interview: 7 Questions to Prepare For

So you have an interview for a Ruby on Rails developer role coming up. Congrats! Rails is a powerful and in-demand framework.

Of course, with a popular technology like Rails, competition for jobs can be stiff. You’ll want to showcase your skills during the interview.

Expect questions that assess your experience with:

• Ruby programming fundamentals
• MVC architecture
• Rails conventions like naming and file structure
• Building web apps and APIs with Rails
• Database integration and ORM
• Debugging and troubleshooting

I’ve compiled a list of 7 common Rails developer interview questions Read on for examples along with tips to craft winning answers,

What is Ruby on Rails?

Rails interviewers often kick things off with a broad question about the framework itself, Be ready to concisely explain

• Rails is a server-side MVC framework written in Ruby for building web applications.

• It emphasizes conventions over configuration, favoring standard ways of doing things.

• Rails follows the “opinionated software” approach to foster best practices.

• It handles defaults for structure, databases, routing and more to accelerate development.

• Key features include Active Record ORM, Action View templates and Action Controller request handling.

Keep your overview high-level and focus on how Rails simplifies and streamlines web development in Ruby. This lays the foundation for more specific questions to come.

Explain the Naming Convention in Rails

Rails relies heavily on conventions like naming for both code clarity and magic shortcuts. Be ready to explain:

• Controllers are named plural like PostsController and live in the app/controllers folder.

• Models are singular like Post and get placed in the app/models folder.

• Views are named like index.html.erb and organized into folders by controller.

• Assets like CSS and JavaScript go in sub-folders under app/assets.

For bonus points, mention how following conventions allows Rails to auto-load classes and wire a lot together. Your grasp of conventions will demonstrate you understand how Rails applications are structured.

What is ORM (Object-Relationship-Model)?

Interviewers want to confirm you understand what ORM is and why it matters:

• ORM stands for Object-Relational Mapping. It provides an interface to a database.

• The database tables and records are modeled as objects and classes.

• This allows accessing and manipulating the data through object methods instead of SQL.

• Active Record is the ORM included with Rails by default. It follows conventions to minimize configuration.

• Using ORM is faster, safer and more Ruby-like than direct SQL. It’s a key reason Rails can boost productivity.

For depth, touch briefly on how Active Record generates SQL behind the scenes when methods like save and find are invoked. Discussing ORM checks the box on a Rails must-know.

What is the Difference Between False and Nil in Ruby?

It’s important to have a solid grasp of Ruby fundamentals before diving into Rails. False vs nil is a common Ruby question:

• False and nil are both “falsy” values, meaning they evaluate to false in conditionals.

• But they are different classes – False is a Boolean while nil represents the absence of a value.

• False will equal false when checked while nil equals nil.

• In Ruby, only nil and false itself are falsy – everything else including 0 and empty strings are truthy.

• Methods like reject and select treat nil and false differently as they are different objects.

Explaining the nuances shows you have more than surface knowledge of Ruby. Take this chance to demonstrate mastery of the language underpinning Rails.

What is the Difference Between String and Symbol?

Here is another opportunity to exhibit your Ruby chops:

• Strings and symbols both represent textual data.

• Symbols are immutable – their value can’t change once created. Strings are mutable.

• Symbols are faster for Ruby to look up vs strings. They’re often used as hash keys or for referencing methods.

• Strings have more methods available like .length as they support more operations.

• Symbols save memory since each unique symbol points to the same object in memory.

• Symbols start with a colon like :my_symbol while strings use quotes like “my string”.

Explaining when to prefer strings vs symbols proves you know how to use Ruby efficiently. This pragmatic knowledge is key for smooth Rails development.

What Command Can You Use to Create a Controller for the Subject?

It’s common in Rails interviews to be asked to demonstrate commands or conventions:

• To generate a controller named SubjectsController, you would use:

rails generate controller Subjects

• This will create app/controllers/subjects_controller.rb and the basic controller class.

• It also generates the views folder app/views/subjects and additional helper, asset and test files.

• The controller name must be plural and CamelCased per the Rails naming convention.

Being able to quickly generate code and components demonstrates real familiarity with Rails. Mentioning key flags like --no-test-framework and --api would also score extra points.

What are some other important Rails interview questions?

While this covers the most common questions, here are a few others worth studying:

• How does routing work in Rails? Know the resources method and path/URL helpers.

• Explain MVC architecture and how it’s implemented in Rails. Know what happens in each layer.

• How does Active Record make working with databases easier? Understand validations, migrations and query interfaces.

• What are some key advantages of using Rails? Productivity, conventions, security and more.

• How do you approach debugging in Rails? Know your logger, server logs, debuggers and error pages.

With this prep, you should feel confident tackling whatever Ruby on Rails interview questions come your way. Remember to play up your strengths designing web apps, APIs and handling complexity. Now go ace that interview!