MySQL is a popular RDBMS that started as an open source project in the mid 1990s. MariaDB is a community-maintained fork of MySQL, intended to serve as a drop-in replacement for MySQL, and to remain available as an open source option in case MySQL (now owned by Oracle) every ceases to be released under an open source license. MySQL and MariaDB are, at the time of writing this book, interchangeable.

Both use the same variant of SQL, with mostly trivial syntax differences from standard SQL that are typically very straightforward. MySQL is—and MariaDB is presumed to be—more optimized for reading/retrieving data than for writing it, but for many applications, those optimizations will likely not be noticeable.

MySQL and MariaDB can be horizontally scaled through the use of clustering and/or replication software additions to a base installation to meet high availability or load needs, though for this to really be effective additional servers (real or virtual) are necessary.

There are several Python libraries for connecting to and interacting with MySQL, and since MariaDB is intended to be able to directly replace MySQL, those same libraries are expected to work without modification for MariaDB access.