How is "data federation" achieved in SAP HANA?

The concept of "data federation" in SAP HANA is primarily achieved through the use of smart data access (SDA). This approach allows SAP HANA to query and retrieve data from non-HANA databases without the need to physically replicate that data into HANA. Instead of moving data, smart data access acts as a bridge, enabling real-time access to external data sources while maintaining the integrity and structure of the original data. This capability is especially beneficial for organizations that want to leverage existing data stores while minimizing data redundancy and synchronization challenges.

The other methods mentioned, while relevant to data management in HANA, do not directly describe the process of data federation. Direct data replication involves bringing copies of data into HANA, which contradicts the principle of federation. Employing external data connectors, while helpful in accessing various data sources, does not specifically encompass the federated querying capabilities that smart data access offers. Server clustering techniques relate more to performance and scalability rather than directly achieving federated access to data.