Definition: In this type of data system, individual source systems maintain control over their own data, but agree to share some or all of this information to other participating systems upon request. System users submit queries via a shared intermediary interface that then searches the independent source systems. Data are queried from source systems and records are matched to fulfill a data requestor’s information needs. The linked data are not stored by the system, but rather, are removed once cached and delivered. The individual sources of data maintain control of their data, storing and securing them, and providing them to the system only upon request.
Source: Taken from Statewide Longitudinal Data System (SLDS) Grant Program, http://nces.ed.gov/programs/slds/pdf/federated_centralized_print.pdf
DaSy Framework Component: System Design and Development