Loosely coupled systems require component databases to construct their own federated schema. A user will typically access other component database systems by using a multi-database language, but this removes any levels of location transparency, forcing the user to have direct knowledge of the federated schema. A user imports the data required from other component databases, and integrates it with their own to form a federated schema.

Tightly coupled systems consist of component systems that use independent processes to construct and publish an integrated federated schema, as illustrated in this figure. The same schema can apply to all parts of the federation, with no data replication.