R4RIN – MCQs, Mock Tests | Ruby on Rails Ruby on Rails Multiple choice Questions Set 3

What command do you run to undo the last 5 migrations

1. rake db:rollback STEP=5
2. database_undo
3. rake db:drop
4. rake db:rollback

✅ Correct Answer: 1

A global variable has a name beginning with:

1. $
2. %
3. @
4. @@

✅ Correct Answer: 1

What gets returned by: [1, [2, 3,[4, 5]]].flatten

1. [1, 2, 3, 4, 5]
2. [1, [2, 3, 4, 5]]
3. [2, 3, [4, 5]
4. ] [1, 2, 3, [4, 5]]

✅ Correct Answer: 1

How can you create a new Rails project?

1. 'rails new /path/to/new/app'
2. 'rails /path/to/new/app'
3. 'rails create /path/to/new/app'
4. None of the above

✅ Correct Answer: 1

Which of the following will delete the key-value 1 from array: "big_data"

1. big_data.del(1)
2. big_data.del[1]
3. big_data.delete(1)
4. None of these

✅ Correct Answer: 3

What is the use of $ in Ruby?

1. $ in Ruby is treated as a class variable
2. $ in Ruby is treated as a global variable
3. both (a) and (b)
4. None of the above

✅ Correct Answer: 2

Which code sample will skip running the login_required "before" filter on the get_posts controller action?

1. Before_action :login_required, skip: [:get_posts]
2. Skip_before_action :login_required, except: [:get_posts]
3. Skip_before_action :login_required, only: [:get_posts]
4. Skip_action before: :login_required, only: [:get_posts

✅ Correct Answer: 3

Which is NOT a default Rails environment?

1. sandbox
2. test
3. development
4. production

✅ Correct Answer: 1

What is a Gem?

1. A configuration item
2. Functionality in a package
3. both (a) and (b)
4. None of the above

✅ Correct Answer: 2

Which extension is default for views html templates?

1. .erb . ..
2. slim
3. rabl
4. haml

✅ Correct Answer: 1

In the MVC pattern:

1. MVC are the initials of the creator, Michael Vincent Clantor.
2. mySQL is the database, vi is the text editor, and C++ is the language.
3. models represent the data, views display the data, and controllers respond to user interactions
4. manipulators handle data, validators ensure data integrity, and communicators transfer information between them.

✅ Correct Answer: 3

What is the command to install Rails?

1. gem install ruby_on_rails
2. gem install ror
3. gem install rails
4. None of the above

✅ Correct Answer: 3

What command do you run to create your database?

1. database_create
2. rake db:migrate
3. rake db:create
4. rails create

✅ Correct Answer: 3

What command do you run to drop your database?

1. rails destroy
2. rake db:drop
3. rake db:migrate
4. database_drop

✅ Correct Answer: 2

How would you declare an Instance Variable?

1. @@
2. @
3. both (a) and (b)
4. None of these

✅ Correct Answer: 2

Ruby uses:

1. null
2. nil
3. both (a) and (b)
4. None of these

✅ Correct Answer: 2

What command do you run to update your database?

1. database_update
2. rake db:migrate
3. rails update
4. rake db:rollback

✅ Correct Answer: 2

Migrations...

1. generally affect only views and sometimes controllers.
2. can never be reversed.
3. back up a project by copying it to another location.
4. modify a database by adding or removing columns or tables.

✅ Correct Answer: 4

What is the preferred method of validating that the name has been set?

1. validates :name, :presence => true
2. save!
3. before_save if name != nil return true end return false end
4. validates :name => not_null

✅ Correct Answer: 1

Which of the following will interpolate within a string with the variable named 'monster'?

1. "/monster"
2. "#{monster}"
3. {monster}
4. "{monster}"

✅ Correct Answer: 2

What is the output of the following ? s="foo" * 2 puts s

1. foo*2
2. foofoo
3. Gives an Error
4. foo

✅ Correct Answer: 2

What ORM does Ruby on Rails use by default?

1. ActiveRails
2. ActiveSupport
3. SQL
4. ActiveRecord

✅ Correct Answer: 4

What is a typical file extension found in the app/controllers directory

1. .yml . .
2. erb
3. .rb
4. html.

✅ Correct Answer: 3

Which of these is not a standard directory in a Rails application?

1. db
2. lib
3. app
4. All of these are standard directories

✅ Correct Answer: 4

The recommended directory in which to place your app's javascript files is:

1. app/assets/javascripts
2. app/javascripts
3. assets/javascripts
4. public/javascripts

✅ Correct Answer: 1

Which files is used to specify any default data that should be loaded into the application's database, when it is first setup?

1. db/default_data.rb
2. db/migrate/inital_load.rb
3. db/migrate/default_data.rb
4. db/seeds.rb

✅ Correct Answer: 4

What is the default value for a global variable (before initialization)?

1. null
2. nil
3. 0
4. nul

✅ Correct Answer: 2

Which of the following prints the "Hello WORLD!" output with a new line?

1. puts "Hello WORLD!"
2. print "Hello WORLD!"
3. disp( "Hello WORLD!" )
4. None of the above

✅ Correct Answer: 1

How do you create a new user object with the name david and save it to the database?

1. User.build(:name => 'david')
2. User.create(:name => 'david')
3. User.new(:name => 'david')
4. User.make(:name => 'david')

✅ Correct Answer: 2

Which of these does NOT correctly return the version of Ruby?

1. -VERSION
2. --version
3. -v
4. None of the above

✅ Correct Answer: 1

If you want the /person url to map to your dog controller and show method, what do you add to your routes?

1. match '/person', :to => 'dog#show'
2. map.resources :person
3. map.resources :dog
4. map.resources :person => :dog

✅ Correct Answer: 1

What is the use of the 'defined?' method?

1. To find the value of a variable
2. To find the memory allocated to that variable
3. To determine if the variable is defined at the current scope
4. To find whether it is a constant or variable

✅ Correct Answer: 3

Which of these javascript frameworks became the default with the release of Rails 3.1?

1. rails.js
2. jQuery
3. rails-script
4. Prototype

✅ Correct Answer: 2

When Ruby methods add an exclamation point at the end of their name (such as sort!), what does it typically indicate?

1. The method executes using
2. Any ending line return will be omitted from the result.
3. The method will ignore exceptions that occur during execution.
4. It is a more powerful or destructive version of the method.

✅ Correct Answer: 4

Which Rails helper would you use in the application view to protect against CSRF (Cross-Site Request Forgery) attacks?

1. Csrf_protection
2. Csrf_helper
3. Csrf_meta_tags
4. Csrf

✅ Correct Answer: 3

In a Rails controller, what does the code params.permit(:name, :sku) do?

1. It filters out all parameters.
2. It filters out submitted form parameters that are not named :name or :sku to make forms more secure.
3. It raises an error if parameters that are not named :name or :sku are found.
4. It raises an error if the :name and :sku parameters are set to nil.

✅ Correct Answer: 2

Review the code below. Which Ruby operator should be used to fill in the blank so that the sort method executes properly? [5,8,2,6,1,3].sort {|v1,v2| v1 ___ v2}

1. =>
2. <==>
3. <=>
4. ||

✅ Correct Answer: 3

Which statement about ActiveRecord models is true?

1. Each database column requres adding a matching attr_accessor declaration in the ActiveRecord model.
2. All attributes in an ActiveRecord model are read-only declared as writable using attr_accessible
3. An instance of an ActiveRecord model will have attributes that match the columns in a corresponding database table.
4. ActiveRecord models can have only attributes that have a matching database column

✅ Correct Answer: 3

Which choice best describes the expected value of @result? @result = Article.first.tags.build(name: 'Urgent')

1. Either true or false
2. An unsaved Tag instance
3. A saved Tag instance
4. An array of Tag instances

✅ Correct Answer: 2

Which part of the Rails framework is primarily responsible for making decisions about how to respond to a browser request?

1. View
2. Controller
3. ActiveRecord
4. Model

✅ Correct Answer: 2

If User is an ActiveRecord class, which choice would be expected to return an array?

1. User.where(last_name: 'Smith')
2. User.find_or_create(last_name: 'Smith')
3. User.find_by_last_name('Smith')
4. User.find('Smith')

✅ Correct Answer: 1

Which choice is not a valid Rails route?

1. Route
2. Match
3. Root
4. Get

✅ Correct Answer: 1

Given a table of blog_posts and a related table of comments (comments made on each blog post), which ActiveRecord query will retrieve all blog posts with comments created during @range?

1. BlogPost.joins (:comments).where(comments: {created_at: @range})
2. BlogPost.where(['comments.created_at', @range])
3. BlogPost.preload (
4. BlogPost.includes (:comments).where('comments.created_at' => @range)

✅ Correct Answer: 1

Which choice is an incorrect way to render a partial?

1. <%= render(:partial => 'shared/product') %>
2. <%= render('shared/product', :collection => @products) %>
3. <%= render(template: 'shared/product', with: @products) %>
4. <%= render('shared/product', locals: { product: @product }) %>

✅ Correct Answer: 3