Using Externally Described Disk Files

Valid Search

Arguments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You can specify a search argument

in

the

ILE RPG

operations

CHAIN,

DEL

READE,

READPE, SETGT, and SETLL that specify a file name

or

a

 

record

name.

For

an

operation to a file name, the maximum number

of

fields

that

you

in

a

search argument

is equal

to

the

total

number

 

of

key

fields

 

valid

key.

For example, if all record types

in

a

file

do

not

contain

all of

fields, you can use a key list

(KLIST)

to

specify

a

search

argument

posed

only of the number of fields common

to

all

record

types in

the

contains

three

record

types,

the

key

fields

are

 

defined

as

follows:

–

REC1

contains

key

field

A.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

–

REC2

contains key fields A and B.

 

 

 

 

 

 

 

 

 

 

 

 

–

REC3

contains

key

fields

A,

B,

and

C.

 

 

 

 

 

 

 

 

 

 

The search argument can only be a single field with attributes identi because field A is the only key field common to all record types. Th ment cannot contain a floating point, variable length, or null-capable field

For an operation to a record name, the maximum number of fields that specify in a search argument is equal to the total number of key fi record type.

If

the search

argument

 

consists

of

one

field, you can specify a lit

or

a

KLIST

name

with one

KFLD.

If

the

search argument is composed of

one field (a composite key), you must

specify a KLIST with multiple KFL

process null-valued keys a

KLIST

must

be used.

 

 

 

 

 

 

The attributes of each field in the

search argument must be identic

butes of the corresponding field in the

file or record key. The att

length,

the

data

type

and the number

of

decimal

positions.

The

attrib

in the key-field-information data table

of

the

compiler

listing. See

the

“Key

Field

Information”

on

page 434.

 

 

 

 

 

 

 

 

 

In all these file operations

(CHAIN,

DELETE, READE,

READPE,

SETGT,

and

 

 

SETLL), you can also specify a search

argument that

contains

fewer

than

number of fields valid for the file

or

record.

Such

a search

argume

partial

key.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Referring to

a Partial

Key

The

rules

for the

specification of a search argument that refers to

as

follows:

 

 

¹The search argument is composed of fields that correspond to the

(high-order) fields of the key for the file or record.

¹Only the rightmost fields can be omitted from the key list (KLIST)

argument

that

refers

to

a

partial

key.

For

example,

if

the total

k

record

is

composed

of

key

fields

A,

B,

and C, the

valid search

a

refer

to

a

partial

key

are field

A,

and

fields A

and

B.

 

¹Each field in the search argument must be identical in attributes sponding key field in the file or record. The attributes include t type, the number of decimal positions, and format (for example, pac zoned).

286 ILE RPG for AS/400 Programmer's Guide

Page 309 Page 311
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IBM AS/400 manual Arguments, Partial Key, Referring to
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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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