How to use module as Namespace in ruby?

 Module or Mix-in used as a Namespace in ruby. It is used to avoid collision between two classes.

module Rajkumar
    class Uthayaa
        attr_accessor :email

        def display_email
            puts "my email is #{@email}"
        end
    end
end

module Somu
    class Uthayaa
        attr_accessor :email

        def display_email
            puts "my email 2 is #{@email}"
        end
    end
end

puts raj = Rajkumar::Uthayaa.new
puts raj.email='rajutaya@gmail.com'
puts raj.display_email
puts raj = Somu::Uthayaa.new
puts raj.email='lalalslsls@gmail.com'
puts raj.display_email

How Database index is functioning?

Indexing is a way to optimize the performance of a database by minimizing the number of disk accesses required when a query is processed. It is a data structure technique which is used to quickly locate and access the data in a database.

Indexes are created using a few database columns.

1. The first column is the Search key that contains a copy of the primary key or candidate key of the table. These values are stored in sorted order so that the corresponding data can be accessed quickly.
2. Note: The data may or may not be stored in sorted order.
3. The second column is the Data Reference or Pointer which contains a set of pointers holding the address of the disk block where that particular key value can be found.

How to install skype on ubuntu 16.04

Kindly run the below commands in terminal for skype installation.

1. Add skype linux repository in your system.

   $ echo "deb [arch=amd64] https://repo.skype.com/deb stable main" | sudo tee /etc/apt/sources.list.d/skype-stable.list

2. To fetch and install Skype public key so that APT package manager verify from repository.

   $ wget https://repo.skype.com/data/SKYPE-GPG-KEY
$ sudo apt-key add SKYPE-GPG-KEY

3. To use https
$ sudo apt install apt-transport-https

4. Update the software source and install skype

$ sudo apt update

 $ sudo apt install skypeforlinux

5. Once installed type skypeforlinux in your application. You can use your skype.