From the Slackware site:

From today's Slackware -current ChangeLog: The big news here is the removal of MySQL in favor of MariaDB. This shouldn't really be a surprise on any level. The poll on LQ showed a large majority of our users were in favor of the change. It's my belief that the MariaDB Foundation will do a better job with the code, be more responsive to security concerns, and be more willing to work with the open source community. And while I don't think there is currently any issue with MySQL's licensing of the community edition for commercial uses, several threads on LQ showed that there is confusion about this, whereas with MariaDB the freedom to use the software is quite clear. Thanks are due to Heinz Wiesinger for his work on transitioning the build script, testing, and getting us all behind this move. He's been working with MariaDB (and their developers) for several years now. Vincent Batts also had a hand in the early discussions here -- he met Daniel Bartholomew of MariaDB on a train last year and got a copy of the source to play with to pass the time on the journey (ah, the miracle of thumbdrives :), and was impressed with not only MariaDB itself, but also with the welcome that Slackware was getting. We expect they'll be responsive to any concerns we have. In the vast majority of situations, MariaDB is entirely compatible with existing MySQL databases and will drop right in with no changes required. There's an article available outlining the areas in which MariaDB differs from MySQL that I'd recommend reading: https://kb.askmonty.org/v/mariadb-versus-mysql-compatibility/

You can see how to use it with perl, at connecting to Maria DB with Perl