Ruby on Rails Interview Questions
Why Rails 5+ uses ApplicationRecord instead of ActiveRecord::Base?
To allow ApplicationRecord to be a single point of entry for all the customizations and extensions needed for an application, instead of monkey patching ActiveRecord::Base. Consider the following example: If you to add some extra functionality to Active Record, this is what you would do in Rails 4.2.
module CustomFeature def interpolate_string puts "Do string interpolation" end end ActiveRecord::Base.include(CustomFeature)
But now, ActiveRecord::Base forever includes CustomFeature and any class inheriting from it also includes CustomFeature even if they don't want it. This is especially true if you are using plugins and engines where monkey patching to ActiveRecord::Base can leak into engine or plugin code. But with ApplicationRecord, they will be localized to only those models which are inheriting from ApplicationRecord, effectively only to your application.
class ApplicationRecord < ActiveRecord::Base include CustomFeature self.abstract_class = true end
What are before, after, around filters/actions in Ruby on Rails? How is it used? Provide relevant examples.
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What are the different types of caching in Ruby on Rails?
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What is GIL and how is it related to concurrency in Ruby?
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Please explain the concept of ActionCable with respect to Ruby on Rails with examples. How does it contribute to real-time application features?
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What are rubygems? Any favorites not including rails? Any that you''ve worked on personally?
rubygems is package manager software for ruby libraries (i.e. gems). The package manager has basic CRUD operations, dependency trees, and supports asynchronous communication between multiple gem servers.
What is ActiveSupport Concern and how is it different from using modules?
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Difference between Preload, Include, Eager Load and Joins in Rails?
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