Hey Ravi, execute the following instructions to install MariaDB on Ubuntu:
Add repositories
sudo apt-get install curl
curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash
sudo apt update
sudo apt install mariadb-server
Update repositories and then install:
apt-get update
apt-get install mariadb-server
Finish the installation by running
/usr/bin/mysql_secure_installation