Hi Venu,
SAP R/3 is a client server model, using 3-tiered architecture. The three layers are
Presentation Layer
Application Layer
Database layer
1) Presentation Layer: Presentation Layer provides means of: Input, allowing the users to manipulate the system Output, allowing the system to produce the results of users manipulation SAP is having Graphical User interface (SAP GUI). The SAP GUI is installed on Individual machines which act as presentation layer.
2) Application Layer: In this layer business logic is executed. The application layer can be installed on one machine, or it can be distributed among more than one system.
3) Database Layer: The database layer holds the data. SAP supports any relational database. SAP does not provide any database. But it supports any RDBMS. The database layer must be installed on one machine or system. Major databases which are being used in SAP implementations are Oracle, DB2.
SAP R/3 is written using its own programming language ABAP. Kernel is written using C language
hope it will helps u and assign points
Venkata Krishna
