ABAP - Wikipedia, The Free Encyclopedia

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Paradigm(s) Object-oriented, structured,

imperative

Appeared in 1983

Designed by SAP AG

Typing discipline Static, strong, safe, nominative

Major

implementations

SAP R/2, SAP R/3

Influenced by Objective-C[ ]

,

COBOL[ ]

,

SQL[ ]

OS Cross-platform

Website http://scn.sap.com

/community/abap

ABAP/4

ABAPFrom Wikipedia, the free encyclopedia

ABAP (Advanced Business Application Programming,

originally ,

German for "general report creation processor"[1]) is a

high-level programming language created by the Germansoftware company SAP. It is currently positioned,

alongside the more recently introduced Java, as the

language for programming the SAP Application Server,

part of its NetWeaver platform for building business

applications. The syntax of ABAP is somewhat similar to

COBOL.[ ]

Contents

1 Introduction

1.1 ABAP runtime environment

1.2 SAP Basis

1.3 SAP systems and landscapes

2 Transactions

3 Types of ABAP programs

4 ABAP Workbench

5 ABAP Dictionary

6 ABAP syntax

6.1 "Hello World"

6.2 Chained statements

6.3 Comments

7 Data types and variables

8 ABAP Objects

9 ABAP statements – an overview

9.1 Declarative statements

9.2 Modularization statements

9.3 Control statements

9.4 Call statements

9.5 Operational statements

9.6 Formatting statements

10 Internal tables in ABAP

11 See also

12 References

13 External links

Introduction

ABAP is one of the many application-specific fourth-generation languages (4GLs) first developed in the

1980s. It was originally the report language for SAP R/2, a platform that enabled large corporations to build

mainframe business applications for materials management and financial and management accounting.

AP - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/ABAP

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ABAP used to be an abbreviation of , German for "generic

report preparation processor", but was later renamed to the English

. ABAP was one of the first languages to include the concept of (LDBs),

which provides a high level of abstraction from the basic database level(s).

The ABAP language was originally used by developers to develop the SAP R/3 platform. It was also

intended to be used by SAP customers to enhance SAP applications – customers can develop custom reports

and interfaces with ABAP programming. The language is fairly easy to learn for programmers but it is not a

tool for direct use by non-programmers. Knowledge of relational database design and preferably also of

object-oriented concepts is necessary to create ABAP programs.

ABAP remains as the language for creating programs for the client-server R/3 system, which SAP first

released in 1992. As computer hardware evolved through the 1990s, more and more of SAP's applications

and systems were written in ABAP. By 2001, all but the most basic functions were written in ABAP. In

1999, SAP released an object-oriented extension to ABAP called ABAP Objects, along with R/3 release 4.6.

SAP's current development platform NetWeaver supports both ABAP and Java.

ABAP runtime environment

All ABAP programs reside inside the SAP database. They are not stored in separate external files like

Java or C++ programs. In the database all ABAP code exists in two forms: source code, which can be

viewed and edited with the ABAP Workbench tools; and generated code, a binary representation somewhat

comparable with Java bytecode. ABAP programs execute under the control of the runtime system, which is

part of the SAP kernel. The runtime system is responsible for processing ABAP statements, controlling the

flow logic of screens and responding to events (such as a user clicking on a screen button); in this respect it

can be seen as a Virtual Machine comparable with the Java VM. A key component of the ABAP runtimesystem is the Database Interface, which turns database-independent ABAP statements ("Open SQL") into

statements understood by the underlying DBMS ("Native SQL"). The database interface handles all the

communication with the relational database on behalf of ABAP programs; it also contains extra features

such as buffering of tables and frequently accessed data in the local memory of the application server.

SAP Basis

The ABAP language environment, including the syntax checking, code generation, and runtime system, is

part of the SAP Basis component/layer. SAP Basis is the technological platform that supports the entire

range of SAP applications, now typically implemented in the framework of the SAP Web Application

Server. In that sense SAP Basis can be seen as the virtual machine on which SAP applications run. Like any

operating system, SAP Basis contains both low-level services (for example memory management, database

communication, or servicing Web requests) and high-level tools for end users and administrators. These

tools can be executables ("SAP kernel") running directly on the underlying operating system, transactions

developed in ABAP, or Web-based programs.

SAP Basis also provides a layer of abstraction between the business applications, the operating system and

database. This ensures that applications do not depend directly upon a specific server or database platform

and can easily be ported from one platform to another.

SAP Basis currently runs on UNIX (AIX, HP-UX, Solaris, Linux), Microsoft Windows, i5/OS on IBMSystem i (formerly iSeries, AS/400), and z/OS on IBM System z (formerly zSeries, S/390). Supported

databases are IBM DB2, Informix, MaxDB, Oracle, and Microsoft SQL Server (support for Informix was

discontinued in SAP Basis release 7.00).


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SAP systems and landscapes

All SAP data exists and all SAP software runs in the context of a . A system consists of a central

relational database and one or more application servers ("instances") accessing the data and programs in this

database. A SAP system contains at least one instance but may contain more, mostly for reasons of sizing

and performance. In a system with multiple instances, load balancing mechanisms ensure that the load is

spread evenly over the available application servers.

Installations of the Web Application Server ( ) typically consist of three systems: one for

development; one for testing and quality assurance; and one for production. The landscape may contain

more systems (e.g., separate systems for unit testing and pre-production testing) or it may contain fewer

(e.g., only development and production, without separate QA); nevertheless three is the most common

configuration. ABAP programs are created and undergo first testing in the development system. Afterwards

they are distributed to the other systems in the landscape. These actions take place under control of the

Change and Transport System (CTS), which is responsible for concurrency control (e.g., preventing two

developers from changing the same code at the same time), version management, and deployment of

programs on the QA and production systems.

The Web Application Server consists of three layers: the database layer; the application layer; and the presentation layer. These layers may run on the same or on different physical machines. The

contains the relational database and the database software. The knowledge contains the

instance or instances of the system. All application processes, including the business transactions and the

ABAP development, run on the application layer. The handles the interaction with users

of the system. Online access to ABAP application servers can go via a proprietary graphical interface, which

is called "SAP GUI", or via a Web browser.

Transactions

A transaction in SAP terminology is the execution of a program. The normal way of executing ABAP code

in the SAP system is by entering a transaction code (for instance, VA01 is the transaction code for "Create

Sales Order"). Transactions can be called via system-defined or user-specific, role-based menus. They can

also be started by entering the transaction code directly into a command field, which is present in every SAP

screen. Transactions can also be invoked programmatically by means of the ABAP statements CALL

TRANSACTION and LEAVE TO TRANSACTION.

The term "transaction" must not be misunderstood here; in the context just described, a transaction simply

means calling and executing an ABAP program. In application programming, "transaction" often refers to an

indivisible operation on data, which is either committed as a whole or undone (rolled back) as a whole. This

concept exists in SAP and is called a LUW (Logical Unit of Work). In the course of one transaction(program execution), there can be different LUWs. Transaction for ABAP Workbench could be invoked

using transaction code SE80 to work on all ABAP development related activities.[ ]

Types of ABAP programs

As in other programming languages, an ABAP program is either an executable unit or a library, which

provides reusable code to other programs and is not independently executable.

ABAP distinguishes two types of executable programs:

Reports

Module pools


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Reports follow a relatively simple programming model whereby a user optionally enters a set of parameters

(e.g., a selection over a subset of data) and the program then uses the input parameters to produce a report in

the form of an interactive list. The term "report" can be somewhat misleading in that reports can also be

designed to data; the reason why these programs are called reports is the "list-oriented" nature of the

output they produce.

Module pools define more complex patterns of user interaction using a collection of screens. The term

“screen” refers to the actual, physical image that the user sees. Each screen also has a "flow logic", which

refers to the ABAP code implicitly invoked by the screens. Each screen has its own flow logic, which is

divided into a "PBO" (Process Before Output) and "PAI" (Process After Input) section. In SAP

documentation the term “dynpro” (dynamic program) refers to the combination of the screen and its flow

logic.

The non-executable program types are:

INCLUDE modules

Subroutine pools

Function groups

Object classesInterfaces

Type pools

An INCLUDE module gets included at generation time into the calling unit; it is often used to subdivide

very large programs. Subroutine pools contain ABAP subroutines (blocks of code enclosed by

FORM/ENDFORM statements and invoked with PERFORM). Function groups are libraries of

self-contained function modules (enclosed by FUNCTION/ENDFUNCTION and invoked with CALL

FUNCTION). Object classes and interfaces are similar to Java classes and interfaces; the first define a set of

methods and attributes, the second contain "empty" method definitions, for which any class implementing

the interface must provide explicit code. Type pools define collections of data types and constants.

ABAP Workbench

The ABAP Workbench contains different tools for editing programs. The most important of these are

(transaction codes are shown in parentheses):

for writing and editing reports, module pools, includes and subroutine pools (SE38)

for processing database table definitions and retrieving global types (SE11)

for designing the user interface (menu bar, standard toolbar, application toolbar,

function key assignment) (SE41)for designing screens and flow logic (SE51)

for function modules (SE37)

for ABAP Objects classes and interfaces (SE24)

The (transaction SE80) provides a single integrated interface into these various tools.

ABAP Dictionary

The ABAP Dictionary contains all metadata about the data in the SAP system. It is closely linked with the

ABAP Workbench in that any reference to data (e.g., a table, a view, or a data type) will be obtained fromthe dictionary. Developers use the ABAP Dictionary transactions (directly or through the SE80 Object

Navigator inside the ABAP Workbench) to display and maintain this metadata.


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When a dictionary object is changed, a program that references the changed object will automatically

reference the new version the next time the program runs. Because ABAP is interpreted, it is not necessary

to recompile programs that reference changed dictionary objects.

A brief description of the most important types of dictionary objects follows:

are data containers that exist in the underlying relational database. In the majority of cases

there is a 1-to-1 relationship between the definition of a table in the ABAP Dictionary and the

definition of that same table in the database (same name, same columns). These tables are known as

"transparent". There are two types of non-transparent tables: "pooled" tables exist as independent

entities in the ABAP Dictionary but they are grouped together in large physical tables ("pools") at the

database level. Pooled tables are often small tables holding for example configuration data.

"Clustered" tables are physically grouped in "clusters" based on their primary keys; for instance,

assume that a clustered table contains "header" data about sales invoices, whereas another clustered

table holds the invoice line items. Each row of H would then be physically grouped with the related

rows from D inside a "cluster table" in the database. This type of clustering, which is designed to

improve performance, also exists as native functionality in some, though not all, relational database

systems.

provide accelerated access to table data for often used selection conditions. Every SAP table

has a "primary index", which is created implicitly along with the table and is used to enforce primary

key uniqueness. Additional indexes (unique or non-unique) may be defined; these are called

"secondary indexes".

have the same purpose as in the underlying database: they define subsets of columns (and/or

rows) from one or - using a join condition - several tables. View is actually a virtual table which does

not contain data physically. Views take very short memory space in database because the views

contain only the definition of data.

are complex data types consisting of multiple fields (comparable to in C/C++).

provide the semantic content for a table or structure field. For example, dozens of

tables and structures might contain a field giving the price (of a finished product, raw material,

resource, ...). All these fields could have the same data element "PRICE".

define the structural characteristics of a data element. For example, the data element PRICE

could have an assigned domain that defines the price as a numeric field with two decimals. Domains

can also carry semantic content in providing a list of possible values. For example, a domain

"BOOLEAN" could define a field of type "character" with length 1 and case-insensitive, but would

also restrict the possible values to "T" (true) or "F" (false).

(successors to the now obsolete "matchcodes") provide advanced search strategies when

a user wants to see the possible values for a data field. The ABAP runtime provides implicit assistance

(by listing all values for the field, e.g. all existing customer numbers) but search helps can be used to

refine this functionality, e.g. by providing customer searches by geographical location, credit rating,

etc.

implement application-level locking when changing data.

ABAP syntax

This brief description of the ABAP syntax begins inevitably with the ubiquitous "Hello World" program.

"Hello World"

REPORT TEST.


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RITE 'Hello World'.

This example contains two statements: REPORT and WRITE. The program displays a list on the screen. In

this case, the list consists of the single line "Hello World". The REPORT statement indicates that this

program is a report. An alternative statement, PROGRAM, would be used for a module pool.

Chained statements

Consecutive statements with an identical first (leftmost) part can be combined into a "chained" statement

using the chain operator ":" (colon). The common part of the statements is written to the left of the colon, the

differing parts are written to the right of the colon and separated by commas. The colon operator is attached

directly to the preceding token, without a space (the same applies to the commas in the token list on, as can

be seen in the examples below).

Chaining is very often used in WRITE statements. WRITE accepts just one argument, so if for instance you

wanted to display three fields from a structure called FLIGHTINFO, you would have to code:

RITE FLIGHTINFO-CITYFROM.

RITE FLIGHTINFO-CITYTO.

RITE FLIGHTINFO-AIRPTO.

Chaining the statements results in a more readable and more intuitive form:

RITE: FLIGHTINFO-CITYFROM, FLIGHTINFO-CITYTO, FLIGHTINFO-AIRPTO.

In a chain statement, the first part (before the colon) is not limited to the statement name alone. The entire

common part of the consecutive statements can be placed before the colon. Example:

REPLACE 'A' WITH 'B' INTO LASTNAME.

REPLACE 'A' WITH 'B' INTO FIRSTNAME.

REPLACE 'A' WITH 'B' INTO CITYNAME.

could be rewritten in chained form as:

REPLACE 'A' WITH 'B' INTO: LASTNAME, FIRSTNAME, CITYNAME.

Comments

ABAP has 2 ways of defining text as a comment:

An asterisk (*) in the leftmost column of a line makes the entire line a comment

A double quotation mark (") anywhere on a line makes the rest of that line a comment

Example:


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***************************************

** Program: BOOKINGS **

** Author: Joe Byte, 07-Jul-2007 **

***************************************

REPORT BOOKINGS.

* Read flight bookings from the database

SELECT

*FROM

FLIGHTINFO WHERE CLASS = 'Y'

OR CLASS = 'C'.

(...)

Data types and variables

ABAP provides a set of built-in data types. In addition, every structure, table, view or data element defined

in the ABAP Dictionary can be used to type a variable. Also, object classes and interfaces can be used as

types.

The built-in data types are:

Type Description

I Integer (4-bytes)

P Packed decimal

F Floating point

N Character numeric

C Character D Date

T Time

X Hexadecimal (raw byte)

STRING Variable-length string

XSTRING Variable-length raw byte array

Date variables or constants (type D) contain the number of days since January 1, 1 AD. Time variables or

constants (type T) contain the number of seconds since midnight. A special characteristic of both types isthat they can be accessed both as integers and as character strings (with internal format "YYYYMMDD" for

dates and "hhmmss" for times), which makes date/time handling very easy. For example, the code snippet

below calculates the last day of the previous month (note: SY-DATUM is a system-defined variable

containing the current date):

DATA LAST_EOM TYPE D.

* Start from today's date

LAST_EOM = SY-DATUM.

* Set characters 6 and 7 (0-relative) of the YYYYMMDD string to "01",

* giving the first day of the current month

LAST_EOM+6(2) = '01'.

* Subtract one day

LAST_EOM = LAST_EOM - 1.

WRITE: 'Last day of previous month was', LAST_EOM.


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All ABAP variables must be explicitly declared in order to be used. Normally all declarations are placed at

the top of the code module (program, subroutine, function) before the first executable statement; this

placement is a convention and not an enforced syntax rule. The declaration consists of the name, type,

length (where applicable), additional modifiers (e.g. the number of implied decimals for a packed decimal

field) and optionally an initial value:

* Primitive types:

DATA : COUNTER TYPE I,

VALIDITY TYPE I VALUE 60,

TAXRATE(3) TYPE P DECIMALS 1,

LASTNAME(20) TYPE C,

DESCRIPTION TYPE STRING.

* Dictionary types:

DATA : ORIGIN TYPE COUNTRY.

* Internal table:

DATA : T_FLIGHTS TYPE TABLE OF FLIGHTINFO,

T_LOOKUP TYPE HASHED TABLE OF FLT_LOOKUP.

* Objects:

DATA : BOOKING TYPE REF TO CL_FLT_BOOKING.

Notice the use of the colon to chain together consecutive DATA statements.

ABAP Objects

The ABAP language supports object-oriented programming, through a feature known as "ABAP Objects".[2]

This helps to simplify applications and make them more controllable.

ABAP Objects is fully compatible with the existing language, so one can use existing statements and

modularization units in programs that use ABAP Objects, and can also use ABAP Objects in existing ABAP

programs. Syntax checking is stronger in ABAP Objects programs, and some syntactical forms (usually

older ones) of certain statements are not permitted.

ABAP statements – an overview

In contrast with languages like C/C++ or Java, which define a limited set of language-specific statements

and provide most functionality via libraries, ABAP contains an extensive body of built-in statements. These

statements often support many options, which explains why ABAP programs look "verbose", especially

when compared with programs written in C, C++ or Java.

This section lists some of the most important statements in the language, subdivided by function. Both the

statements listed here and the subdivision used are fairly arbitrary and by no means exhaustive.

Declarative statements

These statements define data types or declare data objects which are used by the other statements in a

program or routine. The collected declarative statements in a program or routine make up its declaration part.

Examples of declarative statements:


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TYPES, DATA, CONSTANTS, PARAMETERS, SELECT-OPTIONS, TABLES

Modularization statements

These statements define the processing blocks in an ABAP program.

The modularization statements can be further divided into event statements and defining statements:

These are used to define the beginning of event processing blocks. There are no special statements to mark

the end of such blocks - they end when the next processing block is introduced.

Examples of event keywords are:

LOAD OF PAGE,INITIALIZATION,AT SELECTION SCREEN OUTPUT,AT SELECTION SCREEN ON FIELD, AT SELECTION SCREEN ON

AT SELECTION SCREEN, START-OF-SELECTION,END-OF-SELECTION, AT USER-COMMAND, AT LINE-SELECTION,GET,GET LATE,A

AT LINE SELECTION

These statements delineate callable code units such as subroutines, function modules and methods. The

statement marking the end of the unit has the name of the opening statement prefixed with "END".

Examples of defining keywords:

FORM ..... ENDFORM, FUNCTION ... ENDFUNCTION,

MODULE ... ENDMODULE, METHOD ... ENDMETHOD

Control statements

These statements control the flow of the program within a processing block.

Statements controlling conditional execution are:

IF ... ELSEIF ... ELSE ... ENDIF

CASE ... WHEN ... ENDCASE

CHECK

The CHECK statement verifies a condition and exits the current processing block (e.g. loop or subroutine) if

the condition is not satisfied.

Several statements exist to define a loop:

DO ... ENDDO

WHILE ... ENDWHILE

LOOP ... ENDLOOP

DO/ENDDO defines an unconditional loop. An exit condition (typically in the form "IF <condition>. EXIT.

ENDIF.") must be provided inside the body of the loop. A variant (DO <n> TIMES) sets as exit condition

the number of times the loop body is executed. WHILE/ENDWHILE defines a conditional loop. The

condition is tested at the beginning of the loop. LOOP/ENDLOOP loops over the lines of an internal table.

The loop ends after processing the last line of the internal table.


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Call statements

These statements call processing blocks defined using the corresponding modularization statements. The

blocks can either be in the same ABAP program or in a different program.

Examples of call keywords:

PERFORM, CALL METHOD, CALL TRANSACTION, CALL SCREEN, SUBMIT, LEAVE TO TRANSACTION, CALL FUNCTION

Operational statements

These statements retrieve or modify the contents of variables.

A first group of operational statements assign or change a variable:

MOVE, ADD, SUBTRACT, DIVIDE

These statements, whose syntax originates in COBOL, can be written in a shorter form that uses operators

rather than keywords:

MOVE LASTNAME TO RECIPIENT.

* is equivalent to

RECIPIENT = LASTNAME.

ADD TAX TO PRICE.

* is equivalent to

PRICE = PRICE + TAX.

Examples of operational statements on character strings:

SEARCH, REPLACE, CONCATENATE, CONDENSE

Database access statements (Open SQL):

SELECT, INSERT, UPDATE, DELETE, MODIFY

Statements working on internal tables (notice that some "SQL" statements can also be used here):

READ TABLE, LOOP AT, INSERT, DELETE, MODIFY, SORT, DELETE ADJACENT DUPLICATES, APPEND, CLEAR, REFRESH, FREE

Formatting statements

Internal tables in ABAP

Internal tables are an extremely important feature of the ABAP language. An internal table is defined as avector of s in C++ or a vector of objects in Java. The main difference with these languages is that

ABAP provides a collection of statements to easily access and manipulate the contents of internal tables.

Note that ABAP does not support arrays; the only way to define a multi-element data object is to use an


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internal table.[ ]

Internal tables are a way to store variable datasets of a fixed structure in the working memory of ABAP, and

provides the functionality of dynamic arrays. The data is stored on a row-by-row basis, where each row has

the same structure.

Internal tables are preferably used to store and format the content of database tables from within a program.

Furthermore, internal tables in connection with structures are the most important means of defining very

complex data structures in an ABAP program.

Following example define an internal table with two fields with the format of database table VBRK:

DATA : BEGIN OF I_VBRK OCCURS 0,

VBELN LIKE VBRK-VBELN,

ZUONR LIKE VBRK-ZUONR,

END OF I_VBRK.

See also

ERP software

Secure Network Communications

SAP Logon Ticket

Single Sign-On

References

^ "ABAP History". (http://www.sap-technical.com/content/abap/1ABAP%20History.htm)1.

^ "Classes". . [1] (http://help.sap.com/saphelp_nw70/helpdata/en/c3

/225b5c54f411d194a60000e8353423/frameset.htm) accessed 10 August 2009.

2.

External links

SAP Help Portal (http://help.sap.com)

ABAP Development (http://scn.sap.com/community/abap) discussions, blogs, documents and videos

on the SAP Community Network (SCN) (http://scn.sap.com/welcome)

ABAP Objects (http://help.sap.com/saphelp_nw2004s/helpdata/en/ce/b518b6513611d194a50000e8353423/frameset.htm)

ABAP (http://www.dmoz.org/Computers/Software/ERP/SAP/Programming/) at the Open Directory

Project

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