SRTSEQ/ALTSEQ

in

an

RPG

Program

versus a DDS

File . . . . . . . . .279.

Chapter

16.

Accessing

Database

Files

 

 

. . . . . . . . . . . . . . . .

281. . . .

Database Files . . . . . . . . . . . . . . . . . 281

Physical

Files

and

Logical. .Files. . . . . . . . . . . . . . . . . .281

Data Files and Source .Files. . . . . . . . . . . . . . . . . . . .281

Using Externally Described Disk. . .Files

282

Record Format Specifications

282

Access Path

. . . . . . . . . . . 282

Valid Keys for a Record. . or. . File. . . . . . . . . . . . . . . .285

Record

Blocking

and

Unblocking. . . . . . . . . . . . . . . . . . .287

Using Program-Described Disk . Files. . . . . . . . . . . . . . . . . .288

Indexed File . . . . . . . . . . . . . . . . . 288

Sequential File . . .

. . . . . . . . . . . . . .290

Record Address File. . . . . . . . . . . . . . . . . . . . . . . .290

Methods for Processing Disk . Files. . . . . . . . . . . . . . . . . . .291

Consecutive Processing

. . . . . . . . . . . . . .292

Sequential-by-Key Processing . . . . . . . . . . . . 293

Random-by-Key Processing . .

. . . . . . . . . . . 299

Sequential-within-Limits Processing. . . . . . . . . . . 300

Relative-Record-Number Processing. . . . . . . . . . .303

Valid File Operations

304

Using

Commitment

Control

307

Starting

and Ending

Commitment

Control

307. . . .

Specifying

Files

for

Commitment

Control

309. . . .

Using the COMMIT Operation

309

Specifying

Conditional

Commitment

Control. . . . . . . . . . . . . . .311. . .

Commitment

Control

in

the

Program

Cycle. . . . . . . . . . . . . . .312. . .

DDM Files

. . . . .

 

. . . . . . . . . . . . . 312

Using Pre-V3R1 DDM Files. . . . . . . . . . . . . . . . . . . . .313

Chapter

17.

Accessing

Externally

 

Attached

Devices

 

. . . . . . . . . .

315. .

Types of Device .Files. . . . . . . . . . . . . . . . . . . . . . . .315

Accessing Printer Devices

316

Specifying PRINTER Files. . . . . . . . . . . . . . . . . . . . . .316

Handling

Page Overflow

316

Using the Fetch-Overflow Routine in Program-Described. . . . .Files. .320

Changing Forms Control Information in a Program-Described. . . .File.

323

Accessing Tape Devices

325

Accessing Display Devices

326

Using Sequential Files. . . . . . . . . . . . . . . . . . . . . . . . .326

Specifying a Sequential. File. . . . . . . . . . . . . . . . . . . .326

Using

SPECIAL

Files

. . . . . . . . . . . . . . . . . . . . . . . . .327

Example of Using a Special. .File. . . . . . . . . . . . . . . . .329

Chapter

18.

Using

WORKSTN

Files

 

 

 

. . . . . . . . . . . . . . . . .

331

Intersystem

Communications

Function

331

Using Externally Described WORKSTN .Files

331. . . .

Specifying Function Key Indicators on Display. .Device. . . .Files. . 334.

Specifying Command Keys on Display Device. .Files

334. .

Processing

an

Externally

Described

WORKSTN. .File

335. .

Using Subfiles . . .

. .

. . . . . . . . . . . .335

Using

Program-Described

 

WORKSTN

Files

338. . . .

Using a Program-Described

WORKSTN

File

with a Format. . .Name. .

339

viii ILE RPG for AS/400 Programmer's Guide

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IBM AS/400 manual Rpg, Files
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AS/400 specifications

The IBM AS/400, now known as the IBM iSeries, is a midrange computer system that has been a cornerstone of enterprise computing since its introduction in 1988. Designed to provide a robust platform for business applications, the AS/400 is celebrated for its reliability, scalability, and integrated database capabilities.

One of the key features of the AS/400 is its Integrated Operating Environment, which blends hardware and software resources seamlessly. This integration allows businesses to execute diverse workloads, ranging from traditional applications to modern web-based services, all on a single platform. The operating system, OS/400 (now IBM i), offers a rich set of APIs and tools for developers, simplifying application development and management.

Another standout characteristic of the AS/400 is its built-in database, DB2 for i. This powerful relational database management system allows for efficient data handling and provides advanced features such as support for SQL, XML, and JSON, making it easier for businesses to manage their data and integrate it with other systems. The database's tight integration with the operating system enables high performance and security.

In terms of scalability, the AS/400 can accommodate small businesses as well as large enterprises, with the ability to support hundreds of users simultaneously. Its architecture allows for easy upgrades in hardware, meaning that organizations can scale their systems without replacing the entire infrastructure.

Security is another critical attribute of the AS/400. With a sophisticated security model, it offers built-in user authentication, access control, encryption, and auditing capabilities to protect data and applications from unauthorized access.

The AS/400 also supports multiple programming languages, including RPG, COBOL, Java, and PHP, giving organizations the flexibility to choose the development tools that best fit their needs. This diversity helps maintain legacy applications while also developing new ones that leverage modern technologies.

Moreover, the platform supports both traditional green-screen interfaces and modern graphical user interfaces, allowing organizations to transition smoothly into contemporary user experience paradigms.

Overall, the IBM AS/400 stands out as a resilient, flexible, and secure computing platform that enables organizations to effectively manage their business operations, streamline processes, and adapt to changing market demands. Its unique combination of integrated features and capabilities ensures that it remains relevant in today's fast-paced technology landscape.
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