olemus
(a) andmeliidendus: eri allikatest pärit andmete metaandmete agregeerimine selleks määratud tehnoloogia abil
= a type of data virtualization that aggregates data from various sources and provides a single source of data
(b) andmeliidend: tulemuseks saadav agregaat
= the resulting aggregate

ülevaateid
https://browseinfosolutions.com/browseinfosol/clearly-defining-data-virtualization-data-federation-and-data-integration/
https://www.techopedia.com/definition/13789/data-federation-technology
https://www.domo.com/learn/article/a-guide-to-data-federation-everything-you-need-to-know
https://en.wikipedia.org/wiki/Federated_database_system
https://www.semantic-web-journal.net/system/files/swj3074.pdf
https://www.inf.unibz.it/~calvanese/papers/gu-etal-IJCKG-2022.pdf