Defining Externally Described Files

¹

In

the

creation of a new record, the

fields

specified in

the o

 

tions are placed in the record.

Fields not specified in the outpu

 

tions or

not

meeting the

conditions

specified

by

the output

indicat

 

as default values, which depend on the data format specified in

 

description

(for example:

a

blank

for

character

fields; zero

for

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*

.. 1 ...

+...

2 ...+...

3 ...+... 4 ...

+...

5 ...+

... 6

...+

... 7

...+...

*

 

 

OFilename++DF..N01N02N03Excnam++++B++A++Sb+Sa+

 

 

 

*

 

 

OITMREC

D

20

 

 

 

 

 

 

 

 

 

 

 

O

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

N01N02N03Field+++++++++YB.End++PConstant/editword/DTforma￿t++

 

 

O

 

 

 

 

*ALL .1/

 

 

 

 

 

 

 

 

 

 

*

 

 

 

 

 

 

 

 

 

 

 

 

 

OSLSREC

D

30

 

 

 

 

 

 

 

 

 

 

 

O

 

 

 

 

SLSNAM .2/

 

 

 

 

 

 

 

 

 

O

 

 

 

 

COMRAT

 

 

 

 

 

 

 

 

 

O

 

 

 

15

BONUS

 

 

 

 

 

 

 

 

 

 

*

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure

135.

Output Specifications for an Externally Described File

 

.1/ For an update file, all fields in the record are written to described record ITMREC using the current values in the progra fields in the record.

For the

creation

of a

new

record, all fields in

the record

the externally described record ITMREC using the

current values

program

for the

fields

in

the record.

 

.2/ To update a record, the fields SLSNAM and COMRAT are written to externally described record SLSREC when indicator 30 is on. The BONUS is written to the SLSREC record when indicators 30 and 15 on. All other fields in the record are written with the value read.

To create

a new record, the fields

SLSNAM

and

COMRAT

are

writte

the externally described record SLSREC

when

indicator

30

is

on.

field

BONUS

is written

when

indicators

30 and 15 are on. All

o

in the record are written

as

default

values,

which

depend

on

type

(for

example: a

blank

for

character

fields; zero

for

nu

Level Checking

HLL programs are dependent on receiving, at run time, an externally des whose format agrees with what was copied into the program at compilat For this reason, the system provides a level-check function that ensures format is the same.

The RPG

compiler always

provides the information

required

by level

chec

an externally described DISK, WORKSTN, or

PRINTER

file

is

used.

The

lev

check function can be requested on the

create,

change,

and

override

mands.

The default on

the create file

command

is

to

request

level

che

Level checking occurs on a record-format basis when the file is opened specify LVLCHK(*NO) when you issue a file override command or create a the level-check values do not match, the program is notified of the e program then handles the OPEN error as described in Chapter 12, “Handlin Exceptions” on page 217.

270 ILE RPG for AS/400 Programmer's Guide

Page 293 Page 295
Page 294
Image 294
IBM AS/400 manual Level Checking, For Character Fields zero, Is written, All, Slsnam Comrat Bonus
Page 293 Page 295

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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