ABAP : Advanced Business Application Programming
SAP R/3 : SAP Three tier architecture.
R/3 applications are written in the ABAP programming language
The three tier can be described as below:
A further deep into the three layers as described below:
Presentation Layer
-Software components that make up the SAPgui
-Users can log into many Application Servers, in each server 5 sessions are supported.
Application layer
-There could be many Application servers and a message server, with messaing in between the one application server and the other
-The message server is responsible for communication between the application servers.
-The ABAP program runtime environment.
Database Layer
- All data of R/3 System. Like master data, transaction data, Control, customization, program code of application.
- Applications contain program code, screen definitions, menus, function modules. Are called Repository objects.
More on Application layer/Application Server:
Work Processes:
- work processes that can run application.
- Context of the current application.
- Available in each dialog step. (The program logic in an application program that occurs between two screens
is known as a dialog step)
--Screen Processor
- executes the screen flow logic.
-selection screens and Lists
--ABAP-Prozessor
- executes the processing logic of the application program,
- communicates with the database interface.
- The screen processor tells the ABAP processor which module of the screen flow logic should be processed next.
Dispatcher:
-Allocates dialog steps from the SAPgui to a free work process.
-Sends screen output resulting from the dialog step to the user.
Gateway:
-interface for the R/3 communication protocols (RFC, CPI/C).
-To communicate with other application servers in the same R/3 System.
- Other R/3 Systems or with non-SAP systems.
Shared Memory:
- Main memory for all WP.
- Save context in SM.
Database Connection:
- Each WP connected to DB with a dedicated channel
- converts open sql into respective DB commands.
- WP's make changes to DB within a single DB logical unit of work (LUW)
There are different types of work process as deribed below:
1. Dialog: Active user dialog steps to exceute
2. Update: For updating the DB.
3. Background: The process without user interaction.
4. Enqueue: Administer a lock table, since there is one lock table, there is one WP per Application server.
5 Spool:One WP per AS for printing.
Ponder on this:
Can we run ABAP program outside of R/3 basis system.
SAP R/3 : SAP Three tier architecture.
R/3 applications are written in the ABAP programming language
The three tier can be described as below:
1.Presentation layer , a Graphical user interface
2.Application layer
3.Database management system
A further deep into the three layers as described below:
Presentation Layer
-Software components that make up the SAPgui
-Users can log into many Application Servers, in each server 5 sessions are supported.
Application layer
-There could be many Application servers and a message server, with messaing in between the one application server and the other
-The message server is responsible for communication between the application servers.
-The ABAP program runtime environment.
Database Layer
- All data of R/3 System. Like master data, transaction data, Control, customization, program code of application.
- Applications contain program code, screen definitions, menus, function modules. Are called Repository objects.
More on Application layer/Application Server:
Work Processes:
- work processes that can run application.
- Context of the current application.
- Available in each dialog step. (The program logic in an application program that occurs between two screens
is known as a dialog step)
--Screen Processor
- executes the screen flow logic.
-selection screens and Lists
--ABAP-Prozessor
- executes the processing logic of the application program,
- communicates with the database interface.
- The screen processor tells the ABAP processor which module of the screen flow logic should be processed next.
Dispatcher:
-Allocates dialog steps from the SAPgui to a free work process.
-Sends screen output resulting from the dialog step to the user.
Gateway:
-interface for the R/3 communication protocols (RFC, CPI/C).
-To communicate with other application servers in the same R/3 System.
- Other R/3 Systems or with non-SAP systems.
Shared Memory:
- Main memory for all WP.
- Save context in SM.
Database Connection:
- Each WP connected to DB with a dedicated channel
- converts open sql into respective DB commands.
- WP's make changes to DB within a single DB logical unit of work (LUW)
There are different types of work process as deribed below:
1. Dialog: Active user dialog steps to exceute
2. Update: For updating the DB.
3. Background: The process without user interaction.
4. Enqueue: Administer a lock table, since there is one lock table, there is one WP per Application server.
5 Spool:One WP per AS for printing.
Ponder on this:
Can we run ABAP program outside of R/3 basis system.
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