Federated Database
Definition
A federated database system is a type of meta-database management system which transparently maps multiple autonomous database systems into a single federated database. It provides a unified interface to query and manage data from multiple, potentially heterogeneous, data sources.
Why It Matters
In large enterprises, data is often scattered across many different databases (e.g., Oracle, SQL Server, cloud databases). A federated database provides a way to query all of this data as if it were in a single database, without the need for a massive, costly data migration.
Contextual Example
A data analyst needs to create a report that combines sales data from a new cloud application with historical customer data from an old on-premises mainframe. They use a federated query tool (like Presto or Trino) to write a single SQL query that joins data from both sources in real-time.
Common Misunderstandings
- A federated database does not consolidate the data into a single store; it queries the data where it lives.
- This is different from a data warehouse, which involves physically moving data into a central repository via ETL.