Distributed, heterogeneous, federated databases

These popular terms refer to collections of autonomous interoperable databases that model similar or complementary universes [8], [9], [3]. Examples include databases of banks, of hospitals, of car rentals, of restaurants, of jobs... The federated databases are typically subject to multidatabase queries, spanning several databases. A homebuyer may shop for the bank offering the cheapest mortgage. A doctor may need to pump comparative data about an illness from any hospital database accessible. A person may look in a movie in a restaurant databases and for a cinema and a reputable restaurant at the same street, etc.