This chapter introduces you to the heart of data management, namely, the databases. It will introduce you to MariaDB, an open-source relational database management system. Relational essentially means that your data is organized in tables that are related to each other. With its SQL-based query language, it provides a powerful platform for storing, retrieving, and analyzing biological data. Its ability to handle large-scale datasets and complex relationships makes it well suited for a wide range of bioinformatics applications, including genomics, proteomics, and metabolomics. MariaDB’s active community and extensive documentation provide valuable resources for you to leverage its capabilities in you projects. In summary, MariaDB emerges as a versatile and scalable database solution for computational biologists, offering robust features and performance for managing and analyzing biological data effectively. All files from this chapter are available from the book’s GitHub repository at CompBiol3/16_MariaDB .