Multiple-active database systems include at least two database systems that both store a common portion of a relational database. Each database system includes one or more data-storage facilities configured to store data forming the common portion of the relational database in one or more tables and one or more processing modules configured to manage access to the data in the data-storage facilities. One or more management components are configured to distribute database requests directed at the common portion of the relational database among the database systems and to synchronize the data across the database systems when changes are made to the data stored in at least one of the database systems.