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Interview questions for Ruby on Rails developers | Ruby earrings and necklace inside of a grated box.
August 30, 2023 · 4 min read

Interview questions for Ruby on Rails developers

Ruby on Rails developers are in high demand. As a result, companies are competing against one another to hire the best talent.

To hire the best Ruby on Rails developers, you must stand out. Crafting a compelling job description can help you do this. Then, you need to test the skills and knowledge of the developers to see whether they can meet your demands.

Interviews can help you learn more about a candidate’s coding background and test their skills. You’ll get to know your Ruby on Rails developer thoroughly, and you can dig into their applications.

But what interview questions for Ruby on Rails developers should you ask?

Aside from the standard questions like “What have you accomplished?” and “What are your strengths?”, you’ll want to assess your candidate’s knowledge of the framework. 

And in this blog, you’ll find Ruby on Rails interview questions to help you do this.

Ruby on Rails interview questions

Q: What’s the difference between Ruby and Ruby on Rails?


Ruby is a high-level, object-oriented programming language inspired by PERL, Smalltalk, Eiffel, Ada, Basic, and Lisp. 

Ruby on Rails is a framework that developers can use to build web applications in the Ruby programming language.

Ruby and Ruby on Rails sound similar because Ruby programmed Ruby on Rails before releasing it to the public in 2005 – ten years after Ruby.

Q: What is ORM(Object-Relationship-Model)?


In Rails, the Object Relationship Model (ORM) indicates that your classes map to the database table, and objects directly map to the table rows. 

A database may easily store and retrieve the attributes and relationships of application objects using ORM. This model requires less overall database access code and does not require writing SQL queries directly.

Q: What are some advantages and disadvantages of Ruby on Rails?


Advantages of Rails include built-in testing, its open-sourceness, and being completely free to use. Basic solutions are also easy to create. In addition, Rails provides programmers with the opportunity to write code that acts on actual code rather than data.

However, Rails does have its limitations. Features like linking to more than one database at a time, connecting to more than one database server at a time, and foreign keys in databases make it unusable for some programmers.

Arguably its most significant limitation is the complex tools required to build a truly innovative app.

Q: What are Ruby gems?


Ruby gems are libraries created to broaden and improve the capabilities of the language without writing code since the gems contain reusable code. 

Development is more efficient because developers don’t have to code Gems from scratch. 

Q: What is a Rails engine?


Rails applications can be described as compilations of engines that provide various functionalities for the application. Rails engines don’t work on their own. They only function when they become a part of the main Rails application.

Q: Explain Rails Migration.


Rails Migration lets Ruby change the database schema using a version control system that keeps things synchronized with the actual code. This synchronicity means migrations can be rolled back and managed alongside your application source code. 

Rails Migration can do numerous things, including renaming a table, adding a column, changing a column, dropping a table, removing a column, and more.

Q: Explain the role of garbage collection in Ruby on Rails.


Garbage collection is a technique for controlling the amount of memory computer programs use. 

It removes pointer programs and inaccessible objects left behind after the execution of a program to free up memory, letting developers create and destroy objects dynamically without worrying about memory space management. 

Essentially, garbage collection frees up memory for other processes.

Q: How to define Instance Variable, Global Variable, and Class Variable in Ruby?


  • Instance Variable in Ruby begins with– @
  • Class variable in Ruby begins with– @@
  • The global variable in Ruby begins with– $

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