ABAP System Variables

ABAP system variables is accessible from all ABAP programs. These fields are filled by the runtime environment. The values in these fields indicate the state of the system at any given point of time.

The complete list of ABAP system variables is found in the SYST table in SAP. Individual fields of the SYST structure can be accessed either using “SYST-” or “SY-”.

WRITE:/ 'ABAP System Variables'.
WRITE:/ 'Client : ', sy-mandt.
WRITE:/ 'User : ', sy-uname.
WRITE:/ 'Date : ', sy-datum.
WRITE:/ 'Time : ', sy-uzeit.

Output

ABAP Variables

ABAP Variables are instances of data types. Variables are created during program execution and destroyed after program execution.

Use keyword DATA to declare a variable.

DATA: firstname(10) TYPE c,
      index         TYPE i,
      student_id(5) TYPE n.

While declaring a variable we can also refer to an existing variable instead of data type. For that use LIKE instead ofTYPE keyword while declaring a variable.

DATA: firstname(10) TYPE c,
      lastname(10)  LIKE firstname. " Observe LIKE keyword

Structured Variable

Similar to structured data type, structured variable can be declared using BEGIN OFand END OF keywords.

DATA: BEGIN OF student,
      id(5)     TYPE n,
      name(10)  TYPE c,
      dob       TYPE d,
      place(10) TYPE c,
      END OF student.

We can also declare a structured variable by referring to an existing structured data type.

TYPES: BEGIN OF address,
       name(10)   TYPE c,
       street(10) TYPE c,
       place(10)  TYPE c,
       pincode(6) type n,
       phone(10)  type n,
       END OF address. 

Data: house_address  type address,
      office_address like house_address.

Each individual field of the structured variable can be accessed using hyphen (-). For example, name field of the house_address structure can be accessed using housing_address-name.

Character is the default data type.

DATA: true.  " By default it will take C as data type

ABAP Data Types and Constants

Data Type describes the technical characteristics of a Variable of that type. Data type is just the blue print of a variable.

Predefined ABAP Types

DATA TYPE	DESCRIPTION	DEFAULT LENGTH	DEFAULT VALUE
C	Character	1	‘ ‘
N	Numeric	1	0
D	Date	8	00000000
T	Time	6	000000
X	Hexa Decimal	1	X’0′
I	Integer	4	0
P	Packed	8	0
F	Float	8	0

User defined data types
Use TYPES keyword to define the data types.

TYPES: name(10) TYPE c,
       length   TYPE p DECIMALS 2,
       counter  TYPE i,
       id(5)    TYPE n.

Structured data types

Structured data type is grouping of several simple data types under one name.

Use the keywords BEGIN OF and END OF to create a structured data type.

TYPES: BEGIN OF student,
        id(5)     TYPE n,
        name(10)  TYPE c,
        dob       TYPE d,
        place(10) TYPE c,
        END OF student.

Constants

Constants are used to store a value under a name. We must specify the value when we declare a constant and the value cannot be changed later in the program.

Use CONSTANTS keyword to declare a constant.

CONSTANTS: pi  TYPE p DECIMALS 2 VALUE '3.14',
           yes TYPE c VALUE 'X'.

First abap program

Let us write a “Hello SAP ABAP” program.

Navigate to ABAP editor under Tools node in SAP easy access.

Double click on “ABAP Editor” to open the editor. ABAP editor can also be opened by entering t-code SE38 in the command field.

This is the ABAP editor’s initial screen. Enter the name of the program you want to create and press create. All the customer programs must begin with “Y” or “Z”.

In the next popup screen(Program attributes) enter the title for your program, select Executable program as type and press save.

Press Local Object to store the program in the temporary folder.

This is the screen where you can write the ABAP code.

Write the code. Press save, then syntax check( Ctrl + F2 ).

If there are any syntax errors, it ill be displayed at the bottom of the screen as shown above. Correct the errors and again check the syntax.

Successful syntax check message will be displayed in the status bar. Then activate( Ctrl + F3 ) the program.

In the following screen select your program and press continue. Then run(F8) the program.

The output will be displayed as shown above.

SAP Transaction Code

What is SAP transaction code?

SAP Transaction code is a short cut key attached to a screen. Instead of using SAP easy access menu we can also navigate to a particular screen in SAP by entering the transaction code (T-code for short) in the command field of the standard toolbar.

Some of the useful transaction codes for ABAP developers.

T CODE	DESCRIPTION
SE11	ABAP Data Dictionary
SE16	Data Browser
SE37	Function Builder
SE38	ABAP Editor
SE41	Menu Painter
SE51	Screen Painter
SE71	SAP Script Layout
SE80	ABAP Workbench
SE91	Message Maintenance
SE93	Maintain Transaction