How do SAP R/3, ECC and S/4HANA differ?

The three systems follow each other in time, with SAP R/3 being the oldest of the three SAP ERP systems. SAP R/3 came onto the market in 1992. The "R" in the product name stood for "Real-time data processing" and the "3" for the three-stage structure of the system consisting of database, application server and user interface. The successor system SAP ECC also follows this three-tier architecture. The main difference between SAP R/3 and SAP ECC is that ECC is based on Netweaver. Netweaver is a platform (or architecture) for SAP³s business applications and is largely based on the SAP programming language ABAP. Both R/3 and ECC have a modular structure, that is, they consist of certain basic functions ("modules"). SAP R/3 and SAP ECC are both based on relational (line-based) databases, that is, simply put, a large number of tables in which data is stored. SAP S/4HANA, on the other hand, is based on the HANA database, which - unlike the exclusively line-based databases in R/3 or ECC - is also column-based. The in-memory database (use of the working memory as data storage) accesses the data in both columns and rows. Column-based databases can be read more quickly and are therefore better suited for analyzing large data records. Another difference between SAP ECC and SAP S/4HANA: The basic functions (e.g. Finance, Manufacturing or Supply Chain) are no longer referred to as "modules" in SAP S/4HANA, but as "Lines of Business" (LoB). Certain core functionalities of the respective LoB are already integrated in each case - as basic equipment, so to speak; additional functions require an additional license or even an additional installation and license.