Ruby On Rails Interview Questions

The Top Ruby On Rails (ROR) Interview Questions You Need To Know

By Chintan Gor RoR 6 days ago 31 min read 19 Views

Ruby on Rails is a web application framework that is built using the Ruby language. The purpose of this framework is to make it easier to develop web applications by creating assumptions about the resources needed. Today, we will discuss Ruby on Rails Interview Questions.

It makes web applications development a fun experience while reducing the amount of code you need to write. Being an opinionated software, Rails encourages you to follow the most productive way to do things, while often discouraging alternative approaches.

Today several top companies use Ruby on Rails and you might be interviewed for an open position. As such, it is helpful if you have some Ruby on Rails interview questions and their answers prepared that can effectively help you to crack the interview.

If you are a recruiter, and you wish to find out how the candidate expounds on what they know about the subject, these questions can aid you in that endeavor.

Ruby Interview Questions

  1. What Is Ruby on Rails?
  2. What Is Class Library In Ruby?
  3. What Is Naming Convention In Rails?
  4. What Is “Yield” In Ruby on Rails?
  5. What Is ORM In Rails?
  6. What Is The Difference Between False & Nil?
  7. What Are The Positive Aspects Of Rails?
  8. What Are The Role Of sub-directory app/controllers and app/helpers?
  9. What Is The Difference Between String & Symbol?
  10. What Is The Difference Between Symbol & Variables?
  11. What Is Rails Active Record?
  12. How Rails Is Implemented In AJAX?
  13. How To Create A Controller For Subject?
  14. What Is Rails Migration?
  15. What Can Rails Migration Do?
  16. What Is The Command To Create A Migration?
  17. When self.up and self. down Method Is Used?
  18. What Is The Role Of Rails Controller?
  19. What Is The Difference Between Active support’s “HashWithIndifferent” and Ruby’s “Hash”?
  20. What Is Cross-Site Request Forgery (CSRF)?
  21. What Is Mixin In Rails?
  22. How To Define Instance Variable, Global Variable, and Class Variable in Ruby?
  23. How To Run Rails Apps Without Creating Databases?
  24. What Is The Difference Between Callback & Observers?
  25. What Is Rake In Rails?
  26. How To List All Routes For An App?
  27. What Is Sweeper In Rails?
  28. Which Is The Log That Sent Error Report In RoR?
  29. What Is The Difference Between Dynamic & Staff Scaffolding?
  30. What Is The Function Of Garbage Collection In RoR?
  31. What Is The Difference Between Redirect & Render?
  32. What Is The Purpose Of RJs In Rails?
  33. What Is Polymorphic Association In RoR?
  34. What Are The Limitations Of RoR?
  35. What Is The Difference Between Calling super() & Super Call?
  36. What Is Dig, Float & Max?
  37. How To Define Ruby Regular Expression?
  38. What Is Defined Operator?
  39. What Are The New Features Of Ruby?
  40. What Are The Type Of Variables Available In Ruby?
  41. How To Declare A Block In Ruby?
  42. What Is The Difference Between put & putc Statement?
  43. What Is A Class Library In Ruby?
  44. What Is The Scope Of @@name and @name?
  45. What Is The Syntax For Ruby Collect Iterator?
  46. What Is Interpolation In Ruby?
  47. What Is The Notation For Denoting Class Variables In Ruby?
  48. What Is The Difference Between Procs & Blocks?
  49. What Is The Difference Between A Single Quote & Double Quote?
  50. What Is The Difference Between A Gem & Plugin In Ruby?
  51. What Is The Difference Between Extend & Include?
  52. Why Everything Is An Object In Ruby?
  53. Is Ruby Statically Typed or Dynamically?
  54. What Is Getter & Setter In Ruby?
  55. What Happens When A Method Is Called In Ruby?
  56. What Is A Gemfile?
  57. What Is A Gemfile.lock?
  58. What Are Some Of Ruby on Rails Design Pattern?
  59. How Rails Manage Database State?
  60. What Is The Difference Between Count, Length & Size?
  61. What Are Callbacks?
  62. What Are Initializers In Rails?
  63. What Is The Difference Between Delete & Destroy?
  64. What Is PORO?
  65. Does Ruby Allow Multiple Inheritance?
  66. Is Ruby Strongly-Typed or Weakly-Typed?
  67. What Is ActiveRecord?
  68. What Is MVC?
  69. What Is The Difference Between A Proc & A Lamda?
  70. What Is Yield In Ruby?
  71. What Is The Difference Between Hash & JSON?
  72. What Is Your Favorite Ruby Gem?
  73. What Is Spring?
  74. What Is Splat Operator?
  75. What’s A Scope?

1. What Is Ruby on Rails?

This is one of the fundamental Rails interview questions you can ask a candidate.

Ruby: It is a dynamic, object-oriented programming language used for front end and back end development.

Rails: It is a web development framework that gives developers a basic structure upon which they can write their code. It helps them build applications and websites faster by simplifying repetitive tasks.

2. What Is Class Library In Ruby?

One of the most important Ruby on Rails interview questions involves the class library. The class libraries in Ruby consist of various domains like data types and thread programming.

The domains having relevant class libraries are Text processing, Network programming, CGI Programming, XML programming, and GUI programming. These libraries evolve day by day.

3. What Is Naming Convention In Rails?

Variables: Variables should consist of lowercase letters, with each word joined to the other with an underscore.

Class and Module: Classes and Modules use MixedCase, where the first letter of each word is uppercase and there are no underscores between words.

Database Table: Database table names are always plural and they use a snake case, i.e. where all the letters are lowercase and there are underscores between words instead of spaces.

Model: The class names for Model use CamelCase and are always singular.

Controller: The class names for Controller use CamelCase and they are always plural. All of them should have “Controller” as a suffix.

4. What Is “Yield” In Ruby on Rails?

Yield In RoR

While invoking a method, the yield keyword related to a code block facilitates the communication of instructions. Using yield, you can inject a code block into a method.

5. What Is ORM In Rails?

ORM In Rails

Ruby Interview questions often include those about ORM, which is an abbreviation for Object Relational Mapper. This saves us the trouble of retrieving data manually from the Database.

In ORM, there is a single class for every table and while objects correspond to the rows, the attributes correspond to the columns in the table.

6. What Is The Difference Between False & Nil?

In Ruby, false has a boolean value, where nil has no value at all. A method returns either true, false, or nil. False is a FalseClass object, while nil is a NilClass object.

7. What Are The Positive Aspects Of Rails?

The different advantageous features of Rails is a vital part of Ruby technical interview questions and they include:

Meta-programming: Although Rails uses code generation, it resorts to meta-programming for solving complex issues. When it comes to meta-programming, Rails is one of the best languages out there.

Active Record: Rails uses Active Record Framework for saving an object to the database. Using Active Record, you can easily identify a column present in a schema and use meta-programming to bind them to the domain objects.

Scaffolding: Using Rails, you can automatically create a temporary code or scaffolding.

Convention over configuration: Provided you properly follow the naming convention in Rails, you don’t need to perform too much configuration work, in comparison to other development frameworks.

Three environments: Another convenient feature of rails is that there are three separate environments for development, testing, and production.

Built-in testing: Rails has built-in testing features where it writes and executes different test cases.

8. What Are The Role Of sub-directory app/controllers and app/helpers?

App/controllers: This is a subdirectory where Rails searches for the controller classes.

App/helpers: This subdirectory contains helper classes that support the controller, view, and model classes. This subdirectory allows the code in these classes to remain uncluttered, focused, and small.

9. What Is The Difference Between String & Symbol?

One of the most asked Ruby on Rails interview questions is the difference between a symbol and a string. If you use them as key in hashes, both of them yield the same results.

But this does not mean they are one and the same. While String is a mutable object, Symbol is immutable, and cannot be changed once created.

10. What Is The Difference Between Symbol & Variables?

  • You use variables to label an object and they can reference symbols
  • Variables can be used to store character strings, characters, and numeric values
  • Being an internalized string, a symbol resembles a constant
  • Symbols are like immutable strings and the same symbols can be used to label the same object
  • It doesn’t use up any added memory to reference the same symbol multiples times, as they cannot be changed

11. What Is Rails Active Record?

Active Record In RoR

This is often a part of Ruby Senior Developer interview questions. Active Record constitutes the M in the MVC, i.e. the system layer known as Model which represents logic and business data.

It allows you to create and use business objects where you need to persistently store the data in a database. It is an ORM layer following the standard model.

12. How Rails Is Implemented In AJAX?

Rails follow a consistent and simplified model for implementing Ajax. After the rendering and display of the starting web page in the browser, a user can perform various actions to display a brand new web page.

They can also trigger an Ajax operation which is implemented in the following way –

  • Trigger fires: This could be a time-based trigger, the user modifying the data contained in a field or a form, or a clicking of a link or a button.
  • Web client calling the server: The data related to the trigger reaches the action handler with the help of XMLHttpRequest, which is a JavaScript method. This data might be a checkbox id, an entire form, or a text in a field.
  • The server performs processing: Rails controller action works on the data and sends an HTML block to the web client.
  • Response reaches client: Rails generates the client-side JavaScript automatically, which receives the HTML block and updates a certain part of the HTML in the current page with its help.

13. How To Create A Controller For Subject?

This is one of the most important Ruby Programming interview questions. You can create a controller for a table called a subject in the following manner-

C:\ruby\library> ruby script/generate controller Subject

This creates a controller file that you can modify using a text editor.

14. What Is Rails Migration?

Using Rails Migration, you can alter your database in an organized and structured manner. Thus you can use a version control system to synchronize everything with the original code.

15. What Can Rails Migration Do?

Rails Migration can be used for modifying the database structure in the following ways-

  • Create a table
  • Alter a column name in a table
  • Drop a table
  • Rename a column in the table
  • Add a constraint, making sure the value of a particular field in a table is not null
  • Enable the table

16. What Is The Command To Create A Migration?

The Active Record in Rails has a generator that makes creating migrations easy. The command is as follows:

$ rails generate migration AddValueToProduct

This will create a migration like this:

class AddValueToProduct < ActiveRecord::Migration[5.0]

  def change

  end

end

17. When self.up and self.down Method Is Used?

The self.up method is used when migrating up or ahead in time to a new version, whereas the self.down method is used for migrating down or reverting the changes if required.

18. What Is The Role Of Rails Controller?

The role of Rails Controller is the topic of several Ruby on Rails Interview Questions.

  • It is responsible for interpreting the request and producing a suitable output
  • Action controller makes this simpler by the means of smart conventions so it appears straightforward to the developer
  • In most applications, the controller receives the request, save or retrieve data, and create an HTML output using a view
  • A controller acts as the bridge between views and models
  • It allows the view to display the data by making the model data available
  • Updates or saves user data

19. What Is The Difference Between Active support’s “HashWithIndifferent” and Ruby’s “Hash”?

In the core library of Ruby, the Hash class performs a standard “==” key comparison. So you cannot retrieve the value stored in a Symbol using an equivalent String.

HashWithIndifferent, however, is a class inherited from Hash with added special behavior. It treats String keys and Symbol keys as equivalent so you can retrieve the value from a Symbol using String keys.

20. What Is Cross-Site Request Forgery?

Cross Site Request Forgery

CSRF is the subject of several commonly asked Ruby Questions. It is a cyber attack that lets a hacker spoof your server with legitimate requests, posing as an authenticated user.

As a defense against these kinds of attacks, Rails generates unique tokens and with every submission, it validates their authenticity.

21. What Is Mixin In Rails?

A mixin is nothing but a code set that you can add to one or several classes to enhance their capabilities without the help of inheritance.

It is a code contained in a module that can be included or extended by a class. There may be more than one mixins in a single class.

22. How To Define Instance Variable, Global Variable, and Class Variable in Ruby?

Instance Variable: These are variables belonging to a single instance of a class. You can access them from a class instance contained within a method. You don’t need to initialize them and they only have access to a particular class instance. Their names always start with “@”.

Global Variable: You can access global variables from anywhere since they have a global scope. You should minimize their usage as they make the programs complex and difficult to understand. The name of a global variable always begins with a “$”.

Class Variable: You can access these variables from anywhere in a class since they belong to the entire class. You must initialize these variables or an error will pop up. All the descendants of the class share these variables and their names always start with “@@”.

23 .How To Run Rails Apps Without Creating Databases?

  • Eliminate the database gems and run the bundle
  • Modify application.rb, including all the specific Rails part you need
  • Delete any active_record references in the configuration
  • In config/environments/development.rb, there is a reference to the active record that you must remove:
config.active_record.migration_error = :page_load

24. What Is The Difference Between Callback & Observers?

  • Rails Callback: These are methods that are called during vital moments in the life cycle of an object. These include object creation, save, update, validation, or load. You pass callbacks into a function to be invoked once and they are quite short-lived.
  • Rails Observers: This is similar to Callback except for the fact that you use it only when the method has no direct relation to the lifecycle of the object. Also, an observer has a longer lifespan and you can attach and detach them whenever you want.

25. What Is Rake In Rails?

Rake serves a similar purpose as Make in Unix.

You can use it for performing tasks like loading fixtures into the database environment, migrating the database, creating a db/schema.rb file, loading a schema into the database, creating a session table and clearing it, recreating test database, etc.

26. How To List All Routes For An App?

RoR interview questions often involve this one in particular. In order to list all routes for an app, you can run the “rails routes” command from the project folder.

You will thus get a list of all the routes for the Rails application, including its HTTP method and additional information.

27. What Is Sweeper In Rails?

Sweeper is an Observer class that searches for changes made to an object via callbacks, and upon detecting a change, it deletes that object’s cache data. This way, you can get around with several calls in the code.

28. Which Is The Log That Sent Error Report In RoR?

You can see the Apache errors in the Apache error log file in /var/log/apache2/error_log. To find the exact error location, you can run the command passenger-config –detect-apache2. In the development log file, you can find errors in the Ruby code.

29. What Is The Difference Between Dynamic & Static Scaffolding?

Dynamic Scaffolding Static Scaffolding
Creates UI and content automatically at runtime To create data within the fields, you need to enter it manually
Enables the generation of the edit, delete, and new methods Generation is not required
Database synchronization not required Database migration required

30. What Is The Function Of Garbage Collection In RoR?

Ruby Programming Interview Questions often ask about Garbage Collection. Its function is as follows:

  • It allows the elimination of pointer values that remain after the program has stopped executing
  • With Garbage Collection, a programmer no longer needs to track the dynamically created object at runtime
  • It facilitates the removal of those objects from the memory that is inaccessible, thus freeing it and letting other processes use it

31. What Is The Difference Between Redirect & Render?

In certain cases, you want to send the user application to a place not corresponding to the view of the controller action. In this scenario, redirect and render come in handy.

Render tells the program which asset or view it should show the user while being able to access all the defined variables.

Redirect is not the same as Render. This method instructs the browser to send a request. This request goes to another URL and since it is entirely different, the view to which the user will be redirected will not give them access to any of the variables that the controller had defined.

32. What Is The Purpose Of RJs In Rails?

With a conventional Rails template, you can generate XML and HTML files. But RJs templates generate code in JavaScript and this is executed upon its return to the browser. This generated code lets you perform updates on multiple pages using Ajax without refreshing.

Using these RJs templates, you can add some sophisticated Ajax functionality to a Rails application by generating JavaScript code.

33. What Is Polymorphic Association In RoR?

In RoR, a polymorphic association is nothing but an Active Record association that connects a model to multiple others.

So you can use a single association to connect the event and restaurant models with the Review model, which allows us to link a review with a restaurant or an event.

You can find a good example of this association in social media sites where you can comment anywhere, whether it is status updates, links, photos, or videos. Here, polymorphic association prevents you from creating individual comment objects for each of the sections.

34. What Are The Limitations Of RoR?

Ruby on Rails Interview Questions may involve those about its limitations. It is a framework for creating web applications that might not be suitable for other programmers.

Some of its limitations include:

  • Slow runtime speed
  • Lack of flexibility
  • Hard to fix mistakes
  • Inability to link multiple databases at once

35. What Is The Difference Between Calling super() & Super Call?

  • super(): This involves invoking the parent method without any arguments. If the arguments do not match with the parents’ expectations, then super() is suitable.
  • super call: When you call this, Ruby instructs the parent of the object to invoke a method named the same as the one where you called this one from. It also passes the arguments of that method.

36. What Is Dig, Float & Max?

  • When the function is constantly changing, you use the float class
  • When you wish to use decimal digits with float, you use the Dig class
  • The Max class is used when the need for Float is dire

37. How To Define Ruby Regular Expression?

Ruby regular expressions is a series of specially sequenced characters that help you find certain patterns within strings, so you can extract the data and process it further.

Parsing and Validation are two of the main uses of ruby regex. You can also use it to validate an IP address and an email address. Many of the Ruby on Rails interview questions are regex-related.

38. What Is a Defined Operator?

You can use the “defined” operator in Ruby to make sure that a passed expression is defined. If the expression is defined, it returns a descriptive string related to that argument, or else it returns nil.

39. What Are The New Features Of Ruby?

Some particular features are currently dominant in Ruby that you would notice. They are mentioned hereafter.

  • Case sensitive- There is a visible distinction in the lowercase and uppercase letters
  • Free-format- There is no limitation to where exactly you can start writing the program from; any column or line.
  • Statement delimiters- If there are several statements in line, you have to separate it using semicolons. Yet, this is not necessary at the line’s end.
  • Comments- After a line ends, the interpreter ignores anything you add after a # sign if it is unquoted.

40. What Are The Type Of Variables Available In Ruby?

One of the main Ruby on Rails Interview Questions you would face is on variables and its varieties. There are a few specific types of variables present in the programming form named Ruby Class.

  • Global Variables
  • Local Variables
  • Instance Variables
  • Class Variables

41. How To Declare A Block In Ruby?

A Block in Ruby is essentially a manner of grouping coding statements and it appears as the source adjacent to a method call.

Starting at the closing parameter list’s closing parenthesis, you can start the block with the help of a ‘yield statement’. Consequently, the code is generally enclosed with braces ({}) in a block statement.

42. What Is The Difference Between put & putc Statement?

During the Senior Developer Interview Questions, one of the commonly asked questions is on the difference between a putc statement and a put statement.

And the answer is visibly present. In the case of the former, one can use it to output characters, but one by one. As for the latter, one can output the whole string on the screen in one single turn.

43. What Is A Class Library In Ruby?

A Class Library in Ruby contains different types of domains, like data types, thread programming, various domains, and many more.

When you need to create strong Ruby scripts for different types of problem domains, these classes provide flexible capabilities.

The said capabilities come at a high standard of abstraction. There are some specific domains that the class libraries apply to, and they are,

  • Network programming
  • Text programming
  • GUI programming
  • CGI programming

44. What Is The Scope Of @@name and @name?

The two names, @@name and a @ name signify two different variable types in Ruby programming. The @@name is specific to the class variable form; while the @name type refers to the instance variable form.

The former is a class-specific characteristic and requires initialization, while the latter is specific to certain object instances.

45. What Is The Syntax For Ruby Collect Iterator?

In the Ruby Collect Iterator, there is a specific syntax of the collection. It is noticeable as collection.collect.

46. What Is Interpolation In Ruby?

One of the common Ruby Programming Interview Questions is about what Interpolation means in Ruby. When one inserts a literal with a string, the process of doing so is referred to as Ruby Interpolation.

The command for that is specific, and you need to put a Hash sign (#) inside of brackets. In this sequence, the curly bracket type ({}) is applicable.

47. What Is The Notation For Denoting Class Variables In Ruby?

While using Class Variable in Ruby, there are some specific notations that work with each type. They are,

  • The global variable should start with a dollar ($) sign. If the variable is not initialized, the value of it becomes nil and you would receive a warning. You can use it at any point in the program.
  • In the case of a local variable, the name should start with either a lowercase alphabet or an underscore (_) sign.
  • You can start the name of a constant variable with a letter in the uppercase font only. And one cannot define the constant within a method.
  • While using the class variable, the name must start with double @ signs (@@). One needs to initialize it before using it for a method definition.

48. What Is The Difference Between Procs & Blocks?

There are some dissimilarities between Blocks and Procs in Ruby. When asked about it among the Ruby Technical Interview Questions, the following answers are applicable.

  • A Block is not an object, but a Proc is
  • One cannot store blocks within a variable, but they can do so with procs
  • In a list of arguments, a block can appear but only one at most
  • In a method, the Block is its syntax’s part; on the other hand, a ploc has a block’s features

49. What Is The Difference Between A Single Quote & Double Quote?

There is a crucial difference between a Double Quote and a Single Quote in a string. The former can process the escape codes specific to ASCII, but the latter cannot do so.

Plus, double-quoted strings can utilize string interpolation, but the single-quoted ones do not have this capability.

50. What Is The Difference Between A Gem & Plugin In Ruby?

In the case of using a Plugin or a Gem in Ruby, you would notice a certain difference.

  • Plugin- It is a type of ruby code, but you need to install it in the folder of an application. Plus, it is present for the said application specifically that it is used in.
  • Gem- A gem is another specific ruby code. You can install it within the machine itself, and it is operational for all present ruby applications in it.

51. What Is The Difference Between Extend & Include?

In the matter of class in Ruby, there are two particular commands present, specifically, Extend and Include. The Ruby on Rails Interview Questions focuses on the distinctions between them quite frequently.

To elaborate on the said difference, the former presents the methods of the module to the class as a whole. On the other hand, the latter applies these methods to the instance present in a class in particular.

52. Why Everything Is An Object In Ruby?

In terms of object-oriented programming, an instance of each class is called an object. And in Ruby, the class named Class does have instances, and they are all classes. The commands for this are,

  • class => Class
  • class => Fixnum

Thus, in Ruby, most things behave the same way and it makes it easier for you to pick it up as a programming language.

However, a few things like conditional statements (eg., ‘else’), methods, and blocks cannot be called objects. Thus, not everything is completely an object but the maximum of them are.

53. Is Ruby Statically Typed or Dynamically?

One of the most commonly asked Ruby on Rails Interview Questions is if Ruby is Statically typed or it is dynamically typed.

To answer, it is the latter; and that is the reason why you can change the variable type easily during programming. Some particular code lines do not lead to an error if you run them one by one.

54. What Is Getter & Setter In Ruby?

In Ruby, one can define the two methods- the getter, and the setter manually. To specify, you can access a type of instance variable with the help of a getter. On the other hand, you can set up such a variable using the setter.

However, in Ruby, you would get three different accessor methods who perform similarly and in a cleaner way. They are attr_writer (setter), attr_reader (getter), and the unified attr_accessor (getter and setter).

55. What Happens When A Method Is Called In Ruby?

When you are asked this among the Ruby Questions, you have to mention that it is more evident for the Send method of Ruby.

In this, you can send a message with the name of the method to an object. In case the object does contain this method, it would then call it. The common sequences are as follows.

obj.send(:hello) # => 'hello'

obj.hello # => 'hello'

56. What Is A Gemfile?

When one has to specify the dependencies regarding an application of Ruby, it is done in a Gemfile. You can find it in the root directory of the project.

57. What Is A Gemfile.lock?

The Gemfile.lock includes the recorded list of the specific types of gems that one has installed. In case one needs to clone the project into another machine, they can easily install the same versions.

However, if you do not peg the exact version of the gem when specifying it in the Gemfile, the latest version would automatically install.

58. What Are Some Of Ruby on Rails Design Pattern?

One of the common RoR Interview Questions you would receive is regarding the type of design patterns available for Ruby on Rails.

The answer is multiple, and they are policy objects, decorators, service objects, view objects, form objects, value objects, and query objects.

59. How Rails Manage Database State?

In the question of the managing database state, the developer develops and then adds instructions to the migration files manually.

Consequently, this gives ActiveRecord the command to modify the present database state and specifies how to do so.

Thus, it is best not to modify or delete migrations; it can affect the database negatively. When the framework is manually made, one can specify the database end state, and subsequently, the migrations auto-generate. This is notably different from other framework types.

60. What Is The Difference Between Count, Length & Size?

Another of the popular Ruby on Rails Interview Questions is regarding the difference between count, size, and length.

  • Count- An SQL query is rendered to calculate the record numbers. In case the numbers have changed inside the DB vs. Memory, this command is useful.
  • Size- This is another name for length and acts in the same manner as well.
  • Length- Gives back the items present in the memory collection. The weight of this is lighter in comparison to count as it does not require database transactions. Plus, you can use it to calculate the number of the characters available in a specific string.

61. What Are Callbacks?

Callbacks are technically hooks that enter the object life-cycle and you can use it to execute methods. There are different versions present, and they perform tasks regarding objects like updating, making, and even destroying them.

These include after_save, before_validation, and after_destroy respectively. When asked about what it is used for among the RoR Interview Questions, the answer is conditional logic. For example, when you create the User record, you can create a relevant Contact record alongside it.

62. What Are Initializers In Rails?

In Rails, one of the more commonly worded terms you would notice is Initializers. This works after you boot the app, and the purpose of it is to hold the configuration logic.

Therefore, you need to restart the main Rails servers if you change the initializers for it to work properly. In order to find it, open the directory, /config/initializers.

63. What Is The Difference Between Delete & Destroy?

Out of the many Rails Interview Questions that an interviewer would ask, a common one is how to differentiate between Delete command and Destroy command. It is as follows.

Delete- This command is used to remove a record completely.

Destroy- This command removes the records and then performs callbacks.

In terms of the latter, one of the more popular callbacks used in the applications of Rails is associated with model files.

64. What Is PORO?

The full form of PORO is Plain Old Ruby Object. It is important to mention that there are more complex objects in Ruby, especially in the ActiveRecord’s portion.

Thereafter, the term PORO is used, and it stresses on a singularly simple and small object. In terms of business logic, this is used to support it.

65. Does Ruby Allow Multiple Inheritance?

Another of the Senior Developer Interview Questions you would receive is regarding the Multiple Inheritance and its association with Ruby. To elaborate, one can inherit from only a single parent class, and more than is not allowed in Ruby.

However, you can activate the module mixins with ‘extend’ and ‘include’ features as they are permitted under Ruby.

66. Is Ruby Strongly-Typed or Weakly-Typed?

In terms of strength of programming, the typing in Ruby is of the stronger variety. One the other hand, another programming language like JavaScript in particular is weakly typed.

If you use a command of calculation like “hello” + 3 in Ruby, that will throw an error. In contrast, the latter programming language would assess this very calculation. It would turn to “hello3” instead.

67. What Is ActiveRecord?

Interviewers would stress on the aspect of Active Record among the Ruby on Rails Interview Questions. To specify, it is a type of object-relational mapping or ORM. Its main function is to map models according to database tables.

This is highly beneficial for the setup of an app, as it removes a lot of time-consuming duties. These include directly writing the SQL to delete, save, or load objects. Not to mention, a SQL injection cannot cause harm either, as Active Record protects against it.

68. What Is MVC?

RoR MVC Architecture

When Rails is built, it is done around a particular pattern of software design. This is referred to as the Model-View-Controller or MVC. Under this, the information, specifically the way to handle it, is divided into three parts.

The Ruby Technical Interview Questions stress on details, and thus, it is important to mention what each portion does. The first, Model, handles logic and data.

The next, View, refers to the action of displaying the information. And the thirst, Controller takes in the input and then develops the data for View or Model.

69. What Is The Difference Between A Proc & A Lamda?

There are specific differences between a Proc and a Lamda, despite both being stored blocks. The differences are usually visible in the behavior and syntax, with slight variations.

The difference lies in where they return from. The procs come back from inside the method it is a part of, while lamdas come back from themselves.

70. What Is Yield In Ruby?

In Ruby, the yield is responsible for accessing a block that starts working in a method. The files where it mostly functions inside a particular Rails application are the layout files.

During the command process, a notable thing is the printing of “it’s me” after the yield call takes effect. Due to its essential function, it is one of the many potential Ruby on Rails Interview Questions you may get.

71. What Is The Difference Between Hash & JSON?

Hash refers to a class in Ruby, specifically a group of value/key pairs that let keys access values.

JSON is used to send data and is a specifically formatted string.

72. What Is Your Favorite Ruby Gem?

One of the best and most helpful types of Ruby Gems that is a favorite of many Rails developers is Devise. This is the right selection, given how easy it is to set up complex programmings like authentication using it.

Read also: Top 60 Companies That Use Ruby On Rails Regularly

73. What Is Spring?

Spring is one of the important topics of discussion under the Ruby Programming Interview Questions. Specifically, it is a preloader for applications.

It allows the application to run in the background even when you rake tasks or run a migration. Usually, these require rebooting to work, but with the help of Spring, it is not a necessity any longer.

74. What Is Splat Operator?

When you do not want to mention the arguments that you passed in advance to a method you can utilize Splat. There are two types, and they are single and double splat.

The double spat is similar to a single splat, as it performs the same functions. However, it takes values/keys in the form of arguments.

75. What’s A Scope?

You call a type of query logic under Active Record a scope, and many Ruby on Rails Interview Questions focus on this.

One can define the query logic inside of a model and then call it elsewhere. Comparatively, this is more useful than duplicating said logic repeatedly in different parts of the app.

Conclusion

Overall, in terms of preparing for a Ruby on Rails interview, it is important to prepare for probable questions. With the help of the options given here, you can prepare for the interview and revise your knowledge.

Indeed, most of these questions are good for intermediate or junior roles. Thus, you may not get the complete overview of potential questions in full, but it would strengthen your base.

Preparing more would help you in your interview, certainly. But with this question, you would perform suitably well.

We hope you had a great time reading this article and it will help any Ruby on Rails Development Company in the long run. Thank You.!

FAQ

Ruby on Rails programming language is used to build websites and applications by simplifying the complicated & repetitive tasks.

The major downside of Ruby on Rails is that inexperience programmers won’t be able to work with this language.

The simple answer to this question would be NO. RoR is still alive & kicking in 2020 and with few minor updates, it will get better.

In modern web development, there is only one front-end language and that is JavaScript. So, ruby is used for building robust back-end.

Ruby has a bigger presence compared to Python in recent times. So, if you’re looking to move onto web development, learn Ruby.

The simple answer to this question would be YES. Node.js is faster than Ruby on multiple instances.

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Ruby On Rails Interview Questions

Disclaimer: We at eSparkBiz Technologies have created this blog with all the consideration and utmost care. We always strive for excellence in each of our blog posts and for that purpose, we ensure that all the information written in the blog is complete, correct, comprehensible, accurate and up-to-date. However, we can’t always guarantee that the information written in the blog correct, accurate or up-to-date. Therefore, we always advise our valuable readers not to take any kind of decisions based on the information as well as the views shared by our authors. The readers should always conduct an in-depth research before making the final decision. In addition to these, all the logos, 3rd part trademarks and screenshots of websites & mobile apps are the property of the individual owners. We’re not associated with any of them.

Chintan Gor

Chintan Gor

Enthusiastic for web app development, Chintan Gor has zeal in experimenting with his knowledge of Node.js in various aspects of development. He keeps on updating his technical know-how thus pinning his name among the topmost CTO’s in India. His contribution is penned down by him through various blogs on Node.js. He is associated with eSparkBiz – a Node.js Development Company from the past 7-8 years where one can get premium services.

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