ABAP stands for Advanced Business Application Programming. It is a programming language developed by SAP.ABAP language syntax ABAP is not case sensitive. Every statement begins with a keyword and ends with a period.( WRITE is the keyword to print on screen ) WRITE 'Hello World!'. Chained statements. If consecutive statements have identical part at the beginning, then ABAP allows you to chain these statements into a single statement. First write the identical part once and then place a colon (:). Then write the remaining parts of the individual statements separated by commas.Normal Statements: WRITE 'Hello'.WRITE 'ABAP'.Chained Statement:WRITE: 'Hello', 'ABAP'. Comments.If you want to make the entire line as comment, then enter asterisk (*) at the beginning of the line. * This is a comment lineIf you want to make a part of the line as comment, then enter double quote () before the comment.WRITE 'COMMENT'. "Start of commentSAP 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 coDedescription

SE11ABAP Data Dictionary

SE16Data Browser

SE37Function Builder

SE38ABAP Editor

SE41Menu Painter

SE51Screen Painter

SE71SAP Script Layout

SE80ABAP Workbench

SE91Message Maintenance

SE93Maintain Transaction

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 editors 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.ABAP Data Types and ConstantsData Type describes the technical characteristics of a Variable of that type. Data type is just the blue print of a variable.Predefined ABAP TypesData TypeDescriptionDefault LengthDefault Value

CCharacter1

NNumeric10

DDate800000000

TTime6000000

XHexa Decimal1X0

IInteger40

PPacked80

FFloat80

User defined data typesUse 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 typesStructured 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.ConstantsConstants 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'.

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 of TYPE keyword while declaring a variable.DATA: firstname(10) TYPE c, lastname(10) LIKE firstname. " Observe LIKE keywordStructured VariableSimilar 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 typeABAP 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

Basic Operations

Assigning values to ABAP variablesUse = or MOVE keyword to assign a value to a variable.DATA: a TYPE i, b TYPE i, c TYPE i, d TYPE i.a = 10.b = a.MOVE 20 TO c.MOVE c TO d.WRITE:/ a, b, c, d.Output

Basic Arithmetic OperationsDATA: a TYPE i, b TYPE i, c TYPE i, d TYPE i.*Using Mathematical Expressionsa = 10 + 20.b = 20 - 10.c = 10 * 2.d = 100 / 2.WRITE:/ 'Using Expressions'.WRITE:/ a, b, c, d.*Using Keywordsadd 10 to a.subtract 5 from b.multiply c by 2.divide d by 2.WRITE:/ 'Using Keywords'.WRITE:/ a, b, c, d.Output: Clear ABAP variablesUse keyword CLEAR to set the variables to default values.DATA: a TYPE i, b TYPE i.a = 10 + 20.b = 20 - 10.WRITE:/ 'Before Clear'.WRITE:/ a, b.clear: a, b.WRITE:/ 'After Clear'.WRITE:/ a, b.Output

Control Statements

To control the flow of the ABAP program use the following statements.IF Branching ConditionallyIF statement The code between IF and ENDIF is executed only if the condition is true.DATA: a TYPE i VALUE 10. " We can assign a value in the declaration

IF a > 5. WRITE:/ 'Condition True'.ENDIF.Output IF-ELSE statement The code between IF and ELSE is executed if the condition is true, the code between ELSE and ENDIF is executed if the condition is False.DATA: a TYPE i VALUE 1.

IF a > 5. WRITE:/ 'Condition True'.ELSE. WRITE:/ 'Condition False'.ENDIF.Output

IF-ELSEIF statement Used to check multiple conditions.DATA: a TYPE i VALUE 2.

IF a > 5. WRITE:/ a, 'Greater Than', 5.ELSEIF a > 4. WRITE:/ a, 'Greater Than', 4.ELSEIF a > 3. WRITE:/ a, 'Greater Than', 3.ELSE. WRITE:/ a, 'Less Than', 3.ENDIF.Output

CASE-ENDCASE Branching based on the content of the variable.DATA: a TYPE i VALUE 4.

CASE a. WHEN 3. WRITE:/ a, 'Equals', 3. WHEN 4. WRITE:/ a, 'Equals', 4. WHEN OTHERS. WRITE:/ 'Not Found'.ENDCASE.Output

When no condition is met, OTHERS will be executed. OTHERS is not mandatory.LoopsDO ENDDO Unconditional LoopDO can be used to execute a certain lines of codes specific number of times.DO 5 TIMES. WRITE sy-index. " SY-INDEX (system variable) - Current loop passENDDO.Output

WHILE ENDWHILE Conditional LoopWHILE can be used to execute a certain lines of codes as long as the condition is true.WHILE sy-index < 3. WRITE sy-index.ENDWHILE.Output

CONTINUE Terminate a loop pass unconditionally.After continue the control directly goes to the end statement of the current loop pass ignoring the remaining statements in the current loop pass, starts the next loop pass.DO 5 TIMES. IF sy-index = 2. CONTINUE. ENDIF. WRITE sy-index.ENDDO.Output

CHECK Terminate a loop pass conditionally.If the condition is false, the control directly goes to the end statement of the current loop pass ignoring the remaining statements in the current loop pass, starts the next loop pass.DO 5 TIMES. CHECK sy-index < 3. WRITE sy-index.ENDDO.Output

EXIT Terminate an entire loop pass unconditionally.After EXIT statement the control goes to the next statement after the end of loop statement.DO 10 TIMES. IF sy-index = 2. EXIT. ENDIF. WRITE sy-index.ENDDO.Output

String Operations

CONCATENATE Combines 2 or more strings into one string.DATA: s1(10) VALUE 'Hello', s2(10) VALUE 'ABAP', s3(10) VALUE 'World', result1(30), result2(30).CONCATENATE s1 s2 s3 INTO result1.CONCATENATE s1 s2 s3 INTO result2 SEPARATED BY '-'.WRITE / result1.WRITE / result2.Output

If the the concatenated string fits in the result string, then the system variable sy-subrc is set to 0. If the result has to be truncated then sy-subrc is set to 4.SPLIT Splits a string into 2 or more smaller strings.DATA: s1(10), s2(10), s3(10), source(20) VALUE 'abc-def-ghi'.SPLIT source AT '-' INTO s1 s2 s3.WRITE:/ 'S1 - ', s1.WRITE:/ 'S2 - ', s2.WRITE:/ 'S3 - ', s3.Output

If all target fields are long enough and no target fields has to be truncated then sy-subrc is set to 0, else set to 4.SEARCH Searches for a sub string in main string. If found then sy-subrc is set to 0, else set to 4.DATA: string(30) VALUE 'SAP ABAP Development', str(10) VALUE 'ABAP'.

SEARCH string FOR str.IF sy-subrc = 0. WRITE:/ 'Found'.ELSE. WRITE:/ 'Not found'.ENDIF.Output

REPLACE Replaces the sub string with another sub string specified, in the main string. If replaced successfully then sy-subrc is set to 0, else set to 4.DATA: string(30) VALUE 'SAP ABAP Development', str(10) VALUE 'World'.REPLACE 'Development' WITH str INTO string.WRITE:/ string.Output

ABAP Data DictionaryWhat is ABAP Data Dictionary?SQL can be divided into following 2 parts. DML Data Manipulation Language DDL Data Definition LanguageDML part consists of query and update commands like SELECT, UPDATE, DELETE, INSERT etc. ABAP programs handle DML part of SQL.DDL part consist of commands like CREATE TABLE, ALTER TABLE, DROP TABLE, CREATE INDEX etc. ABAP Dictionary handles DDL part of SQL.So ABAP Dictionary is used to create and manage data definitions (metadata). ABAP Dictionary is used to create Tables, Data Elements, Domains, Views, Lock Objects etc.What are Data Elements and Domains?While creating a table in data dictionary each table field is assigned to a data element. Each data element is in turn assigned to a domain. Domain describes the technical attributes such as data type and length of a table field. Data Element gives the field labels and documentation for the table field.Consider the following code. PARAMETERS is the keyword to create input fields.PARAMETERS: p_matnr TYPE matnr.Output

In order to get the field labels use the menu in the ABAP editor GOTO->Text Elements->Selection Texts.

All the input fields will be displayed in a table.

Just check the Dictionary Ref checkbox and press enter.

The Text ( Field Label ) will be automatically read from the Data Element. Now save, activate, go back and run the program again.

Now place the cursor on the input field and press F1 key to get the documentation from the data element.Actually this field label and documentation are maintained in the Data Element MATNR.So if we want to create a table with two fields as FirstName and SecondName, then only one domain is sufficient with data type as CHAR and length say 20. But we need two different data elements in order to display different field labels and documentation for both the fields.

How to create a domain in SAP?To create a domain go to t-code SE11.

Select the Domain radio button, enter the the name of the domain that you want to create and press create.Enter the short description. Place the cursor in the data type and press F4 to get the list of SAP data types.

In the popup window select the correct data type.

Enter the number of characters. Enter the decimal places if it applicable to data type that you have selected. Save and activate the domain.How to create a Data Element in SAP?To create a data element, go to t-code SE11.

Select the Data type radio button, enter the name of the data element and press create.

Select the Data Element radio button and press continue.

Enter short description. Assign a domain to the data element. Press field label tab to maintain the field labels for the data element.Enter the field labels, Save and activate the data element.How to create a SAP table?Every table has a unique name and consists of rows and columns. The number of columns in a table is fixed but can have any number of rows.ABAP dictionary handles the DDL part of SQL in SAP. Go to ABAP dictionary (SE11) to create a SAP table. Enter the name of the table to be created and press enter.

Enter a proper short description for the table and maintain delivery class as A(Application Table). Now press on Fields tab to maintain the fields of the table.Enter the fields of the table and maintain the proper data elements for the table fields. You can use the standard data elements or you can create your own data elements.Maintain the primary key and press save. To maintain the technical attributes of table like tablespace, size etc. press the Technical attributes button on application toolbar.

Enter Data class, Size category and Save.

Now press back, save and activate the table.Maintain test data in SAP tableAfter creating a table you can test it by maintaining a couple of entries in the table. Follow the below mentioned procedure to maintain entries in the table. But this procedure must be used only in testing or development environment not in production environment.Display the table in ABAP Dictionary (SE11). Use the menu path Utilities->Table Contents->Create Entries.

If this menu path is disabled then go to Delivery and Maintenance tab andenter Display/Maintenance Allowed in Data Browser/Table View Maint. listbox.

Save and activate the table. Then go back to menu path Utilities->Table Contents->Create Entries.

Enter some test values in the fields and press save.

Observe the message in the status bar. To display the values in the table go to Utilities->Table Contents->DisplayIn the selection screen enter the selection criteria if you want to filter the records you want to display and press execute.

All the records in the table will be displayed if no selection criteria specifiedin the selection screen.What are Primary Keys and Foreign Keys?A primary key is a field or group of fields that uniquely identify a record in a table. Primary key fields cannot be NULL and cannot contain duplicate values.If you want to link two tables, then primary key of one table will be added to another table where primary key of first table will be become the foreign key of second table.Consider the following two tables.Department TableDepartment_ID (Primary Key)Department_Name

01Computers

02Physics

03Electronics

Employee TableEmployee_ID (Primary Key)NamePlace

001JimNew York

002JackLondon

003RobinSydney

004RajBangalore

If you want to link department table and employee table, then add the primary key of department table i.e. Department_ID to employee table. Department_ID becomes the foreign key of employee table and Department table becomes the check table.Employee table after creating foreign key.Employee_ID (Primary Key)NamePlaceDepartment_ID (Foreign Key)

001JimNew York01

002JackLondon01

003RobinSydney02

004RajBangalore03

The main purpose of the foreign key is data validation. This will not allow entering a Department_ID in the employee table that is not there in the department table. For example if you try to create a record in employee table with Department_ID as 04, it will throw an error.How to create a Foreign Key in SAP table?The purpose of the foreign key is to validate the data that is being entered into a table by checking entries in a check table. Foreign keys are checked by the front end user interface only and it is not checked if you issue a direct a SQL statement to update the database.Follow the steps given below to create a foreign key in SAP table.Step 1: Open the table in Data Dictionary (SE11) for which you want to create a foreign key. Select the field for which you want to create the foreign key and press Foreign Keys button.Step 2: In the popup window enter the check table name and press Generate proposal button.Step 3: The system proposes the foreign key relation based on the domain. Check that the foreign key relationship proposed by the system is correct and press copy.Foreign key is created, now save and activate the table. To check the foreign key go to menu path Utilities->Table Contents->Create Entries.

Try to create an entry in Zemployee table with Department ID that is not there in the Department table. Enter the values and try to save the entry.

Observe the error message in the status bar. The user interface does the foreign key validation before creating the entries.