Overview
Data Federation is a specific implementation of data virtualization. It involves creating a 'federated' view that allows users to query multiple autonomous databases as if they were a single system. The federated engine decomposes the query, sends sub-queries to the source systems, and aggregates the results.
Key Characteristics
- Autonomy: Source databases remain independent and managed locally.
- Heterogeneity: Can combine data from different types of databases (e.g., SQL and NoSQL).
- Virtualization: No data is moved to a central repository.
Challenges
- Performance can be limited by the slowest source system or network latency.
- Complex query optimization across different engines.