Quark (/ˈkwɔrk/ or /ˈkwɑrk/) is a federation layer over the databases in a analytics stack. It provides a federated schema that maps tables in multiple database systems. With the help of the federated schema, Quark makes it possible to define and use materialized views, olap cubes and other relationships between tables stored in different databases. Quark comes with a simple execution layer that redirects queries to use materialized views or cubes. Quark is distributed as a JDBC jar and will work with most tools that integrate through JDBC.