MySQL is an very fast relational database management system (RDBMS). It is a free and viable alternative to an expensive commercial RDBMS such as Oracle or Microsoft SQL Server. Although it is not as fully featured as those commercial products, it does provide the core RDBMS features necessary to implement enterprise-class software and also performs on-par with most commercial products.

MySQL and INDI

INDI utilizes a PHP database abstraction layer that supports both MySQL and PostgreSql (the latter is also a free RDBMS). However, due to its performance and ease of deployment and maintenance, MySQL is the recommended RDBMS for INDI.