Methods for Processing Disk Files

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

*

PROGRAM NAME:

ESWLIM2

 

*

* RELATED FILES:

EMPMST

(Physical File)

*

*

 

LIMITS

(Physical File)

*

*

 

PRINT

(Printer File)

*

*

DESCRIPTION:

This program shows the processing of an

*

*

 

externally described file sequentially

*

*

 

within limits.

*

*

 

This program prints out information for the

*

*

 

employees whose employee numbers are within

*

*

 

the limits given in the file LIMITS.

*

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

FLIMITS

IR

F

6

3

DISK

RAFDATA(EMPMST)

FEMPMST

IP

E

 

L

K DISK

 

FPRINT

O

F

80

 

PRINTER

 

*Input Specifications are optional for an externally desc￿ribed

*file. Here, *IN01 is defined as the record-identifying

*indicator for the record-format EMPREC to control the

*processing of this record.

IEMPREC

 

01

 

 

OPRINT

H

1P

1

 

O

 

 

12

'SERIAL #'

O

 

 

22

'NAME'

O

 

 

45

'DEPT'

O

 

 

56

'TYPE'

O

D

01

1

 

O

 

ENUM

10

 

O

 

ENAME

35

 

O

 

EDEPT

45

 

O

 

ETYPE

55

 

O*

 

 

 

 

Figure 154. Sequential-within-Limits Processing of a Program-Described File

Relative-Record-Number Processing

Random

input

or

update processing

by

relative

record number

applies

dural files only. The desired record is accessed by the

CHAIN

 

ope

Relative

record

numbers

identify

the

positions

of

the

records

relat

ning

of

the file. For example, the relative record numbers of the

seventh

records are 1, 5, and 7, respectively.

 

 

 

 

 

 

For

an

externally

described

file,

input

or

update

processing

by

rel

number

is

determined by

a blank

in

position

34

of

the

file

descrip

and the use of the CHAIN operation

 

code.

Output

processing

by

rela

number

is determined by a blank

in

position

34

and

the

use

of

the

on

the

file

 

description

specification

line

for

the

file.

 

 

 

 

Use the RECNO keyword on a file

description specifications

to

speci

field

that contains the relative record number that specifies

where

to

be

added to this file. The RECNO field must be defined as num

decimal

positions. The field length must be large enough

to

contain

t

record

number

for

the

file.

A RECNO

 

field

must

be

specified

if

 

ne

be

placed

in

the

file

by

using

output

specifications

or a

WRITE

o

Chapter 16. Accessing Database 303Files

Page 327
Image 327
IBM AS/400 manual Relative-Record-Number Processing, ESWLIM2 Related Files Empmst, Fempmst Disk Fprint

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.