Top 72 Ruby on Rails Interview Questions And Answers

Question 1

Explain what is ORM (Object-Relationship-Model) in Rails?

Accepted Answer

ORM or Object Relationship Model in Rails indicate that your classes are mapped to the table in the database, and objects are directly mapped to the rows in the table.

Question 2

Mention what is Rails _Migration_?

Accepted Answer

Rails Migration enables Ruby to make changes to the database schema, making it possible to use a version control system to leave things synchronized with the actual code.

Question 3

Explain what is Ruby on Rails?

Accepted Answer

* Ruby: It is an object-oriented programming language inspired by PERL and Python
* Rails: It is a framework used for building web applications

Question 4

Explain what is _rake_ in Rails?

Accepted Answer

**Rake** is a Ruby Make; it is a Ruby utility that substitutes the Unix utility ‘make’, and uses a ‘Rakefile’ and ‘.rake files’ to build up a list of tasks. In Rails, Rake is used for normal administration tasks like migrating the database through scripts, loading a schema into the database, etc.

Question 5

What Is ORM In Rails?

Accepted Answer

**ORM** tends for Object-Relationship-Model, where Classes are mapped to table in the database, and Objects are directly mapped to the rows in the table.

Question 6

What Do You Mean By `Render` And `Redirect_to`?

Accepted Answer

* _render_ causes rails to generate a response whose content is provided by rendering one of your templates. Means, it will direct goes to view page.

* *redirect_to* generates a response that, instead of delivering content to the browser, just tells it to request another url. Means it first checks actions in controller and then goes to view page.

Question 7

What Are _Helpers_ And How To Use Helpers In ROR?

Accepted Answer

**Helpers** are modules that provide methods which are automatically usable in your view. They provide shortcuts to commonly used display code and a way for you to keep the programming out of your views. The purpose of a helper is to simplify the view.

Question 8

Mention what is the role of Rails _Controller_?

Accepted Answer

The Rails **controller** is the logical center of the application. It facilitates the interaction between the users, views, and the model. It also performs other activities like

* It is capable of routing external requests to internal actions. It handles URL extremely well
* It regulates helper modules, which extend the capabilities of the view templates without bulking of their code
* It regulates sessions; that gives users the impression of an ongoing interaction with our applications

Question 9

What Are The Various _Components_ Of Rail?

Accepted Answer

1. **Action Pack**: Action Pack is a single gem that contains Action Controller, Action View and Action Dispatch. The "VC" part of "MVC".

* Action Controller: Action Controller is the component that manages the controllers in a Rails application. The Action Controller framework processes incoming requests to a Rails application, extracts parameters, and dispatches them to the intended action.

* Action View: Action View manages the views of your Rails application. It can create both HTML and XML output by default. Action View manages rendering templates, including nested and partial templates, and includes built-in AJAX support.

* Action Dispatch: Action Dispatch handles routing of web requests and dispatches them as you want, either to your application or any other Rack application. Rack applications are a more advanced topic and are covered in a separate guide called Rails on Rack.

2. **Action Mailer**: Action Mailer is a framework for building e-mail services. You can use Action Mailer to receive and process incoming email and send simple plain text or complex multipart emails based on flexible templates.

3. **Active Model**: Active Model provides a defined interface between the Action Pack gem services and Object Relationship Mapping gems such as Active Record. Active Model allows Rails to utilize other ORM frameworks in place of Active Record if your application needs this.

4. **Active Record**: Active Record are like Object Relational Mapping (ORM), where classes are mapped to table, objects are mapped to columns and object attributes are mapped to data in the table.

5. **Active Resource**: Active Resource provides a framework for managing the connection between business objects and RESTful web services. It implements a way to map web-based resources to local objects with CRUD semantics.

6. **Active Support**: Active Support is an extensive collection of utility classes and standard Ruby library extensions that are used in Rails, both by the core code and by your applications.

Question 10

What is the use of `load` and `require` in Ruby?

Accepted Answer

* You use `load()` to execute code 
* use `require()` to import libraries.

Top 72 Ruby on Rails Interview Questions

Mention what is Rails Migration?

Explain what is rake in Rails?

Explain what is ORM (Object-Relationship-Model) in Rails?

Explain what is Ruby on Rails?

What Is ORM In Rails?

Mention what are the positive aspects of Rails?

How Is Visibility Of Methods Changed In Ruby (encapsulation)?

What do you mean by the term Scaffolding and what sort of advantages the Ruby can offer when it comes to same?

Explain how you define Instance Variable, Global Variable and Class Variable in Ruby?

What Are The Various Components Of Rail?

How Many Types Of Relationships Does A Model Has?

What Are Helpers And How To Use Helpers In ROR?

What Do You Mean By Render And Redirect_to?

What is the use of load and require in Ruby?

Mention what is the difference between a gem and a plugin in Ruby?

How Many Types Of Associations Relationships Does A Model Have?

Mention what is the role of Rails Controller?

Mention what are the limits of Ruby on Rails?

What Is MVC? And How It Works?

Explain what is a class library in Ruby?

Explain what is Rails Active Record in Ruby on Rails?

Explain what is the role of sub-directory app/controllers and app/helpers?

List out what can Rails Migration do?

What Is The Difference Between Nil And False In Ruby?

Mention what is the difference between the Observers and Callbacks in Ruby on Rails?

Explain what is Interpolation in Ruby?

Explain what is Polymorphic Association in Ruby on Rails?

What Things We Can Define In The Model?

What exactly are Harnesses and Fixtures in the Ruby?

What is the difference between &&, || operators and and, or?

Can you explain the difference between ActiveSupport’s HashWithIndifferentAccess and Ruby’s Hash?

What is the difference between symbol and string?

What Is The Difference Between Delete And Destroy?

What Is A Proc?

Mention what is the difference between calling super() and super call?

What is the use of Destructive Method?

What Are Filters?

How does Ruby on Rails use the Model View Controller (MVC) framework?

How should you use nested layouts?

What is the purpose of the rakefile available in the demo directory in Ruby?

Mention what is the function of garbage collection in Ruby on Rails?

Mention what is the purpose of RJs in Rails?

What is the difference between content_for and yield?

How would you choose between Belongs_to And Has_one?

What Is The Difference Between Save And Save!?

What is ActiveJob? When should we use it?

What is the Difference Between Gem And Plugin?

What Are Filters? And How Many Types Of Filters Are There In Ruby?

What is the difference between string and text in Rails?

What Do You Mean By Naming Convention In Rails?

What are Strong Parameters?

What is Rack?

Does Ruby Support Single Inheritance/Multiple Inheritance Or Both?

What Is The Flash?

How Many Types Of Callbacks Available In RoR?

Explain the difference between Page, Action, Fragment, Low-Level, SQL caching types.

Is Rails Scalable?

What sort of problems you have faced with Ruby on Rails and how do you think the same can affect the projects?

Node.js vs Ruby on Rails. Which would you choose?

What is Dynamic Finders?

What is the best thing which you find about the Ruby on Rail so far?

What is Asset Pipeline?

What is a Rails engine?

How To Use Two Databases Into A Single Application?

What is the purpose of the resources method in the code snippet below?

Mention what is the difference in scope for these two variables: @@name and @name?

Explain Ruby on Rails Exception Handling

Practical test: Genres of music

How to rollback a specific migration?

How To Find Second Max Element From Database?

How to check if a specific key is present in a hash or not?

How Do I Find Only Duplicate Entries In A Database Table?

What Do You Mean By `Render` And `Redirect_to`?

What is the use of `load` and `require` in Ruby?

What Is The Difference Between `Nil` And `False` In Ruby?

What is the difference between `&&`, `||` operators and `and, or`?

Can you explain the difference between ActiveSupport’s `HashWithIndifferentAccess` and Ruby’s `Hash`?

What is the difference between `symbol` and `string`?

What Is The Difference Between `Delete` And `Destroy`?

What Is A `Proc`?

Mention what is the difference between calling `super()` and `super call`?

What is the purpose of the `rakefile` available in the demo directory in Ruby?

What is the difference between `content_for` and `yield`?

How would you choose between `Belongs_to` And `Has_one`?

What Is The Difference Between `Save` And `Save!`?

What is `ActiveJob`? When should we use it?

What is the difference between `string` and `text` in Rails?

Mention what is the difference in scope for these two variables: `@@name` and `@name`?

How to check if a specific key is present in a `hash` or not?