SAP HANA stores data for processing primarily in columnar format. But unlike other columnar databases, HANA’s columnar store was designed from the beginning to be efficient for all databases operations (reads, writes, updates). In practice, 99% of the database tables in SAP ERP are columnar tables, including transactional and master data tables.
HANA can also store data in row format, but this is primarily used to store configuration information and queues – only scenarios for which the column store is specifically not suited. With HANA, data is stored once, in its most granular form, and aggregated on request. There is no hybrid row/column store, no duplication or replication of data between row and column stores – HANA stores the data in the column store only.