Ruby On Rails Interview Questions and Answers

Ques 1. Explain the difference between a has_one and belongs_to association in Ruby on Rails.

Ques 2. What is a Proc?

Procs, short for procedures, act similar to blocks, but can be saved as variables and reused. Think of them as blocks you can call over and over again on multiple arrays.

Ques 3. What are the three levels of method access control for classes and what do they signify? What do they imply about the method?

• Public, protected, and private.

• Public methods can be called by all objects and subclasses of the class in which they are defined in.

• Protected methods are only accessible to objects within the same class.

• Private methods are only accessible within the same instance.

• Be able to explain why this does (or doesn’t matter), and when you would want to set a method as private.

Ques 4. What is the convention using ‘!’ at the end of method name?

The ! indicates that the method is about to change the object itself.

Here’s an example:

foo = "A TEST STRING"  # a string called foo

foo.downcase!     # modifies foo permanently
a test string

puts foo          # prints modified foo
a test string

Similarly if you did not want the object to be changed you could have something simple like:

foo2 = "A 2nd Test String"  # a string called foo 

foo2.downcase     # modifies foo temporarily
a 2nd test string 

puts foo2 nbsp;    # prints original foo 
A 2nd Test String