Architecture exposes the structure of a system while hiding the implementation details. Architecture also focuses on how the elements and components within a system interact with one other. Software design delves deeper into the implementation details of the system.
SAP R/3 is a 3 tier architecture consisting of 3 layers
In simple words, it’s a client server architecture.
- Rsignifies Real-time system
- 3represents – 3-tier architecture.
User’s PC:- Users can access SAP system in two ways:-
- Through SAP GUI
- Through Web browser
It’s called front-end. Only the front-end is installed in the user’s PC not the application/database servers.
Front-end takes the user’s requests to database server and application servers.
Database and Application may exist on the same or different physical location.
Understanding different SAP layers
The Presentation Layer contains the software components that make up the SAPgui (graphical user interface). This layer is the interface between the R/3 System and its users. The R/3 System uses the SAPgui to provide an intuitive graphical user interface for entering and displaying data.
The presentation layer sends the user’s input to the application server, and receives data for display from it. While a SAPgui component is running, it remains linked to a user’s terminal session in the R/3 System.
The Application Layer consists of one or more application servers and a message server. Each application server contains a set of services used to run the R/3 System. Theoretically, you only need one application server to run an R/3 System. In practice, the services are distributed across more than one application server. The message server is responsible for communication between the application servers. It passes requests from one application server to another within the system. It also contains information about application server groups and the current load balancing within them. It uses this information to assign an appropriate server when a user logs onto the system.
The Database Layer consists of a central database system containing all of the data in the R/3 System. The database system has two components – the database management system (DBMS), and the database itself. SAP has manufactured its own database named hana but is compatible with all major databases such as Oracle.All R/3 data is stored in the database. For example, the database contains the control and customizing data that determine how your R/3 System runs. It also contains the program code for your applications. Applications consist of program code, screen definitions, menus, function modules, and various other components. These are stored in a special section of the database called the R/3 Repository, and are accordingly called repository objects. R/3 repository, objects are used in ABAP workbench.