ABAP high level programing language

ABAP (Advanced Business Application Programming) is a high-level programming language developed by SAP SE specifically for building business applications within the SAP ecosystem. Since its inception in the 1980s, ABAP has evolved significantly, adapting to new technologies and business needs while remaining the core language for customizing and extending SAP systems. This comprehensive overview will delve into ABAP's history, architecture, syntax, key features, development environments, and its role in modern SAP landscapes.

1. History and Evolution of ABAP

ABAP was created in 1983 by a team at SAP, led by Dietmar Hopp, to address the need for a language tailored to business data processing. Early versions were procedural and focused on batch processing, but over time, ABAP has undergone major transformations:

    •    1990s: Introduction of ABAP/4 (4th generation), which added support for interactive applications (e.g., SAP GUI screens) and database integration.

    •    2000s: Shift toward object-oriented programming (OOP) with ABAP Objects, aligning with industry standards.

    •    2010s: Integration with web technologies, such as ABAP Web Dynpro for web-based UIs, and compatibility with SAP HANA, a in-memory database.

    •    2020s: ABAP Cloud (part of SAP BTP) emerged, enabling cloud-native development with a focus on modularity, security, and scalability.

Today, ABAP remains critical for SAP S/4HANA, SAP ERP, and other SAP solutions, supporting both on-premises and cloud deployments.

2. ABAP Architecture and Ecosystem

ABAP programs run within the SAP NetWeaver Application Server, which acts as a middleware layer connecting the user interface, application logic, and database. Key components of the ABAP ecosystem include:

    •    SAP NetWeaver Application Server (AS ABAP): The runtime environment for ABAP programs, handling execution, memory management, and communication with databases (e.g., SAP HANA, Oracle, SQL Server).

    •    Database Layer: ABAP interacts with databases via Open SQL, a standardized SQL dialect that abstracts database-specific syntax, ensuring portability across different database systems.

    •    Presentation Layer: Users interact with ABAP applications through interfaces like SAP GUI (desktop), Web Dynpro (web), or Fiori (modern, responsive UIs).

    •    SAP Repository: A central storage system for ABAP objects (programs, classes, screens, etc.), managed via the ABAP Development Tools (ADT) or classic SE80 transaction.

3. ABAP Program Types

ABAP supports various program types to cater to different business scenarios:

    •    Executable Programs (Type 1): Standalone programs started directly by users (e.g., reports). Created using the REPORT statement.
Example:
REPORT ZMY_FIRST_REPORT.
WRITE 'Hello, ABAP!'.
    •    Module Pools (Type M): Used for interactive applications with multiple screens (e.g., data entry forms). Built with MODULE-POOL and managed via screen painter (SE51).

    •    Include Programs (Type I): Reusable code snippets inserted into other programs to avoid redundancy. Defined with INCLUDE.

    •    Function Groups (Type F): Collections of function modules (reusable subroutines) for specific tasks (e.g., data validation). Created via SE37.

    •    Classes and Interfaces (OOP): Object-oriented constructs for modular, maintainable code. Defined using CLASS and INTERFACE statements.

4. Procedural vs. Object-Oriented ABAP

ABAP supports both procedural and object-oriented paradigms, with OOP becoming increasingly dominant for modern development.

Procedural ABAP

Relies on subroutines, function modules, and global data. Key elements include:

    •    Subroutines: Defined with FORM and called with PERFORM.
Example:
FORM display_message.
  WRITE 'This is a procedural message.'.
ENDFORM.

PERFORM display_message.
    •    Function Modules: Encapsulated procedures stored in function groups, accessed via CALL FUNCTION.

    •    Global Data: Variables declared in the main program, accessible across subroutines.

Object-Oriented ABAP (ABAP Objects)

Introduced in 1999, ABAP Objects supports classes, objects, inheritance, polymorphism, and encapsulation.

    •    Classes: Blueprints for objects, defined with CLASS ... DEFINITION (structure) and CLASS ... IMPLEMENTATION (methods).
Example:
CLASS ZCL_MY_CLASS DEFINITION.
  PUBLIC SECTION.
    METHODS: display_message.
ENDCLASS.

CLASS ZCL_MY_CLASS IMPLEMENTATION.
  METHOD display_message.
    WRITE 'This is an OOP message.'.
  ENDMETHOD.
ENDCLASS.
    •    Objects: Instances of classes, created with CREATE OBJECT.
Example:
DATA(lo_object) = NEW ZCL_MY_CLASS( ).
lo_object->display_message( ).
    •    Inheritance: Classes can inherit attributes and methods from a superclass using INHERITING FROM.

    •    Interfaces: Collections of abstract methods that classes can implement, ensuring consistency.

5. ABAP Syntax and Core Elements

ABAP syntax is English-like and case-insensitive, with strict rules for structure and formatting.

Data Types and Variables

ABAP offers a rich set of data types, including:

    •    Elementary Types: I (integer), F (floating-point), C (character), D (date), T (time), STRING (dynamic character string), XSTRING (binary string).

    •    Complex Types: Structures (STRUCTURE), internal tables (dynamic arrays), and references (REF TO).

Variables are declared using DATA:
DATA: lv_integer TYPE I VALUE 100,
      lv_text    TYPE STRING VALUE 'ABAP Programming',
      lv_date    TYPE D.
Internal Tables

A fundamental feature for storing and processing tabular data in memory. Internal tables support various operations like sorting, filtering, and aggregation.

    •    Types of Internal Tables:

    ◦    Standard tables: Index-based, unsorted.

    ◦    Sorted tables: Sorted by key, faster for key-based access.

    ◦    Hashed tables: Optimized for key-based lookups using a hash algorithm.

    •    Declaration and Usage:
" Define an internal table with a structure
TYPES: BEGIN OF ty_employee,
         id   TYPE I,
         name TYPE STRING,
       END OF ty_employee.

DATA(lt_employees) TYPE STANDARD TABLE OF ty_employee.

" Insert data
APPEND VALUE #( id = 1 name = 'John Doe' ) TO lt_employees.
APPEND VALUE #( id = 2 name = 'Jane Smith' ) TO lt_employees.

" Loop through the table
LOOP AT lt_employees INTO DATA(ls_employee).
  WRITE: / ls_employee-id, ls_employee-name.
ENDLOOP.
Control Structures

ABAP supports standard control flow statements:

    •    Conditionals: IF-ELSE-ENDIF, CASE-WHEN-ENDCASE.
Example:
DATA(lv_score) = 85.

IF lv_score >= 90.
  WRITE 'Excellent'.
ELSEIF lv_score >= 70.
  WRITE 'Good'.
ELSE.
  WRITE 'Needs improvement'.
ENDIF.
    •    Loops: DO (count-controlled), WHILE (condition-controlled), LOOP AT (internal table iteration).

Database Interaction

ABAP uses Open SQL to interact with databases, ensuring compatibility across systems. Key statements include:

    •    SELECT: Retrieve data from database tables.
Example:
" Select data from SAP's standard customer table (KNA1)
SELECT *
  FROM kna1
  INTO TABLE @DATA(lt_customers)
  WHERE land1 = 'US'. " Filter for US customers
    •    INSERT, UPDATE, DELETE: Modify database records, with implicit or explicit commits.

6. ABAP Development Tools

Developers use specialized tools to create and maintain ABAP code:

    •    ABAP Development Tools (ADT): Based on Eclipse, ADT is the modern IDE for ABAP development, supporting OOP, debugging, and integration with SAP HANA. It replaced the classic ABAP Workbench (SE80) for most tasks.

    •    ABAP Workbench: A set of transactions in SAP GUI (e.g., SE38 for programs, SE24 for classes, SE11 for data dictionary) used for legacy development.

    •    Debugger: A powerful tool to step through code, inspect variables, and analyze runtime behavior (accessed via /h in SAP GUI or ADT).

    •    Code Inspector (SCI): Checks code for performance, security, and compliance with SAP standards.

7. Key Features for Business Applications

ABAP includes features tailored to enterprise needs:

    •    SAP Dictionary: A central repository for data definitions (tables, views, data elements), ensuring data consistency across the system.

    •    Batch Input/Output (BATCH INPUT): Automates data entry into SAP transactions, useful for migrating data from legacy systems.

    •    ALE (Application Link Enabling): Facilitates data exchange between distributed SAP systems.

    •    Workflow: Automates business processes (e.g., approval workflows) using ABAP-based rules and tasks.

    •    Enhancements and Modifications:

    ◦    User Exits: Predefined hooks in SAP standard code for custom logic.

    ◦    Business Add-Ins (BAdIs): Object-oriented enhancements that allow customization without modifying standard code.

8. ABAP and SAP HANA

With the introduction of SAP HANA (in-memory database), ABAP evolved to leverage its speed and capabilities:

    •    ABAP for HANA: Optimizes code to run on HANA, using features like:

    ◦    Core Data Services (CDS): Defines data models and views directly in HANA, improving performance by pushing logic to the database layer.
Example CDS View:
@EndUserText.label: 'Customer Sales View'
define view ZC_CUSTOMER_SALES as select from kna1
  join vbak on kna1.kunnr = vbak.kunnr
{
  key kna1.kunnr as CustomerID,
      kna1.name1 as CustomerName,
      sum(vbak.netwr) as TotalSales
}
group by kna1.kunnr, kna1.name1;
    ◦    AMDP (ABAP Managed Database Procedures): Allows writing SQLScript (HANA's native language) within ABAP classes for high-performance database operations.

    •    Code Pushdown: Moves data processing logic from the application server to HANA, reducing data transfer and improving speed.

9. ABAP Cloud and Modern Development

ABAP Cloud, part of SAP Business Technology Platform (BTP), enables cloud-native development with:

    •    Restricted ABAP: A subset of ABAP with stricter rules (e.g., no global data, mandatory OOP) to ensure scalability and security in the cloud.

    •    Integration with SAP Fiori: ABAP Cloud services can expose OData APIs to power Fiori apps, creating modern user experiences.

    •    DevOps Support: Integration with Git, CI/CD pipelines, and automated testing tools (e.g., ABAP Test Cockpit) for agile development.

10. Career and Certification in ABAP

ABAP developers are in high demand due to the widespread use of SAP systems. Key certifications include:

    •    SAP Certified Development Associate - ABAP with SAP NetWeaver

    •    SAP Certified Development Specialist - ABAP for SAP HANA

Skills required: Proficiency in ABAP syntax (procedural and OOP), SAP Dictionary, database integration, and familiarity with SAP modules (e.g., SD, MM, FI).

Conclusion

ABAP is a versatile, business-focused language that remains integral to the SAP ecosystem. From its procedural roots to modern object-oriented and cloud-native implementations, ABAP continues to evolve, enabling developers to build robust, scalable applications that drive enterprise operations. Its integration with SAP HANA and cloud platforms ensures its relevance in the digital transformation era, making it a valuable skill for developers working with SAP systems.