3 Must know SAP Internal Tables Types and Operations Guide

SAP ABAP (Advanced Business Application Programming) plays a critical role in data processing within SAP systems. One of its key concepts is the internal table, a powerful structure used to handle and manipulate data dynamically during program execution. In this article, we will explore SAP internal tables, their types, common operations, and the concept of work area in detail.

What is an Internal Table in SAP?

An internal table in SAP ABAP is a temporary storage structure used to store and process data during program execution. Unlike database tables, internal tables reside in application server memory and are primarily used for structured data processing within an ABAP program.

Internal tables are particularly useful for handling large datasets retrieved from database tables, processing data before updating the database, and exchanging data between different parts of a program.

Types of Internal Tables in SAP

SAP ABAP provides three main types of internal tables, each serving different purposes:

1. Standard Table

A standard table is the most common type of internal table. It has a linear index and allows access to records sequentially or via an index. Searching for records in a standard table without an index requires a linear search, which may impact performance for large datasets.

Example of Standard Table Declaration

DATA: lt_materials TYPE TABLE OF mara.

Here, lt_materials is an internal table that holds data from the MARA (Material Master) table.

2. Sorted Table

A sorted table is an internal table that maintains records in a sorted order based on the primary key. It allows binary searches, making data retrieval faster than in a standard table.

Example of Sorted Table Declaration

DATA: lt_sorted_materials TYPE SORTED TABLE OF mara WITH UNIQUE KEY matnr.

Here, lt_sorted_materials stores material data sorted by the MATNR field.

3. Hashed Table

A hashed table uses a hashing algorithm to store and retrieve records quickly. This type of table is ideal for scenarios where frequent key-based access is required, but it does not support index-based access like standard or sorted tables.

Example of Hashed Table Declaration

DATA: lt_hashed_materials TYPE HASHED TABLE OF mara WITH UNIQUE KEY matnr.

This declaration creates a hashed table where MATNR is the unique key, ensuring fast key-based access.

Internal Table Operations

ABAP provides various operations to handle and manipulate internal tables efficiently. Below are some of the most common operations:

1. Populating an Internal Table

Data can be inserted into an internal table using the SELECT statement or manually with APPEND and INSERT.

Fetching Data from a Database Table

SELECT * FROM mara INTO TABLE lt_materials WHERE mtart = 'RAW'.

This statement fetches all materials of type ‘RAW’ and stores them in lt_materials.

Appending Data Manually

DATA: wa_material TYPE mara.
wa_material-matnr = '1001'.
wa_material-mtart = 'ROH'.
APPEND wa_material TO lt_materials.

This manually appends a record to the internal table.

2. Reading Data from an Internal Table

Data retrieval can be done using READ TABLE or looping through the internal table.

Using READ TABLE

DATA: wa_material TYPE mara.
READ TABLE lt_materials INTO wa_material WITH KEY matnr = '1001'.
IF sy-subrc = 0.
  WRITE: 'Material found:', wa_material-mtart.
ENDIF.

This searches for a material with MATNR = '1001' and stores the result in wa_material.

3. Modifying Data in an Internal Table

Data in an internal table can be modified using MODIFY.

Updating an Entry

READ TABLE lt_materials INTO wa_material WITH KEY matnr = '1001'.
IF sy-subrc = 0.
  wa_material-mtart = 'FERT'.
  MODIFY lt_materials FROM wa_material.
ENDIF.

This updates the MTART field of the material 1001 to FERT.

4. Deleting Data from an Internal Table

Records can be removed using DELETE.

Deleting a Record by Key

DELETE lt_materials WHERE matnr = '1001'.

This removes the record where MATNR = '1001'.

5. Sorting an Internal Table

Sorting helps arrange data in ascending or descending order.

SORT lt_materials BY matnr ASCENDING.

This sorts lt_materials by MATNR in ascending order.

Understanding Workarea in SAP

A workarea is a temporary variable that holds a single row of an internal table. It is used for processing records one at a time before inserting, reading, modifying, or deleting data in an internal table.

Declaring and Using a Workarea

DATA: wa_material TYPE mara.
LOOP AT lt_materials INTO wa_material.
  WRITE: wa_material-matnr, wa_material-mtart.
ENDLOOP.

Here, wa_material holds each row of lt_materials one at a time during the loop execution.

Best Practices for Working with Internal Tables

Choose the Right Table Type: Use hashed tables for quick key-based access, sorted tables for sorted data, and standard tables for general storage.
Minimize Data Load: Fetch only required fields instead of using SELECT * to improve performance.
Use Proper Indexing: Define keys correctly in sorted and hashed tables for efficient retrieval.
Optimize Search Operations: Use READ TABLE ... WITH KEY and binary search for better performance.
Avoid Unnecessary Loops: Use table operations like MODIFY, DELETE, and SORT instead of unnecessary loops.

Know more on SAP

SAP Internal Tables: Types, Operations, and Work area Explained