Install MariaDB (an RDB forked from MySQL).

Install

Install, then the package will take care of everything.

sudo apt install mariadb-server

Now, it’s ready to use.

MariaDB in Debian is secure by default

You may find articles recommending mysql_secure_installation, but there is no need to run it.
Check /usr/share/doc/mariadb-server/README.Debian.gz for more details.

There is absolutely no need to run the script mariadb-secure-installation or (mysql_secure_installation) after installing MariaDB with apt install mariadb-server. The script is useless, and very misleading with reporting “Success!” after every step even if it did nothing.

Interface for PHP/Ruby/Python

Interface modules to connect to MariaDB. For example, CMS (mainly by PHP) will require php-mysql interface.

sudo apt install php-mysql ruby-mysql2 python3-mysqldb