Final answer:
SAP S/4HANA uses a columnar data model facilitated by the SAP HANA database, providing improved data processing and real-time analytics.
Step-by-step explanation:
The data model used for SAP S/4HANA is the columnar data model. This model is a key feature of the SAP HANA database, which underlies SAP S/4HANA. It is specifically designed to optimize the performance of both transactional and analytical processes by allowing fast data retrieval and processing. This is accomplished by storing data tables by columns rather than by rows, which is typical in traditional relational databases. The benefit of the columnar data model is that it significantly reduces the data footprint and allows for real-time analytics and computations, which are core advantages of SAP S/4HANA.