What Is Data Structure in Rpgle?


Angela Bailey

What Is Data Structure in Rpgle?

Data structure is a fundamental concept in the world of programming. It provides a way to organize and store a collection of related data items. In the context of Rpgle, a programming language used primarily for business applications on IBM iSeries systems, data structures play a crucial role in managing and manipulating data.

The Basics of Data Structure

At its core, a data structure is a user-defined composite type that combines different data elements into a single unit. This allows for efficient storage and retrieval of related information. Rpgle supports various types of data structures, including arrays and nested structures.


An array is a fixed-size collection of elements, all of the same data type. It provides an indexed way to access individual elements within the collection.

In Rpgle, you can define an array using square brackets ([]). For example:

DCL <arrayName>       CHAR(10) DIM(5);

This declares an array named <arrayName> with 5 elements, each capable of storing up to 10 characters.

Nested Structures:

A nested structure allows you to group multiple data items together into one larger structure. Each item within the structure can have its own individual data type.

To define a nested structure in Rpgle, you use the DCL-DS statement followed by END-DS to indicate the end of the structure definition. Here’s an example:

DCL-DS <structureName>
  <element1>     CHAR(10);
  <element2>     INT(5);

This declares a nested structure named <structureName> with two elements: <element1>, which can store up to 10 characters, and <element2>, which can store a 5-digit integer.

The Benefits of Using Data Structures

Data structures offer several advantages in Rpgle programming:

  • Organization: By grouping related data items together, data structures provide a logical and organized way to represent complex information. This makes code more readable and maintainable.
  • Ease of Access: With data structures, you can access individual elements within the structure by referencing their names or indices.

    This simplifies data manipulation and reduces the chance of errors.

  • Memory Efficiency: Data structures optimize memory usage by allocating memory only for the required elements. This helps conserve system resources.

Working with Data Structures in Rpgle

To make use of a data structure in Rpgle, you need to declare it before using it in your code. Once declared, you can assign values to its individual elements and perform operations on them.

Assigning Values:

To assign a value to an element within a data structure, you use the dot notation followed by the element name. For example:

<structureName>.<element1> = 'Hello';
<structureName>.<element2> = 42;

This assigns the value ‘Hello’ to <element1> and the value 42 to <element2> within <structureName>.

Data Manipulation:

You can manipulate data within a data structure using various operations, such as concatenation, mathematical calculations, and string manipulation.<element1> = <structureName>.<element1> + ‘ World’;

This concatenates the value of <element1> with the string ‘ World’, resulting in ‘Hello World’.


Data structures are an essential tool for managing and organizing data in Rpgle. They provide a way to group related information together, making code more readable and efficient. By understanding the basics of data structures and how to work with them, you can enhance your Rpgle programming skills and build robust business applications.

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