Using

 

Program-Described

 

Disk

Files

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*..

1

...+...

2 ...

+...

3

...+

... 4

...+...

5

...+...

6 ...

+

... 7

..*

 

 

A

T.Name++++++.Len++TDpB

Functions++++++++++++++++++++*

 

 

A

 

R FORMATA

 

 

 

PFILE(ORDDTLP)

 

 

 

 

 

 

A

 

 

 

 

 

 

 

TEXT('Access Path for Indexed +

 

 

A

 

 

 

 

 

 

 

File')

 

 

 

 

 

 

 

A

 

FLDA

 

 

14

 

 

 

 

 

 

 

 

 

 

A

 

ORDER

 

 

5

0

 

 

 

 

 

 

 

 

 

A

 

FLDB

 

 

101

 

 

 

 

 

 

 

 

 

 

A

 

K ORDER

 

 

 

 

 

 

 

 

 

 

 

 

 

A*

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*..

1

...+...

2 ...

+...

3

...+

... 4

...+...

5

...+...

6 ...

+

... 7

...+...

*

 

FFilename++IPEASFRlen+LKlen+AIDevice+.Keywords+++++++++++++++++++++++++++++

 

FORDDTLL IP

F

118

 

3PIDISK

KEYLOC(15)

 

 

 

 

 

 

F*

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure

141. DDS and corresponding File-Description Specification Detail Flow of RPG IV

Exception/Error

Handling

 

 

 

 

 

 

 

 

 

 

 

 

You must use data description specifications to create the access program-described indexed file.

In the DDS for the record format FORMATA for the logical file ORDDTLL ORDER, which is five digits long, is defined as the key field, and format. The definition of ORDER as the key field establishes the k this file. Two other fields, FLDA and FLDB, describe the remaining po record as character fields.

The program-described input file ORDDTLL is described on the file d specifications as an indexed file. Positions 29 through 33 must spec of positions in the record required for the key field as defined

positions.

The

KEYLOC

keyword specifies position 15 as the starting po

key field

in

the

record. Because the file is defined as program-

position 22, the ILE RPG compiler does not retrieve the external fi

description

of

the

file

at

compilation time. Therefore, you must des

the

record

on

the

input

specifications.

 

 

 

 

 

 

 

 

 

 

 

*..

1 ...

+...

2 ...

+...

3

...

+...

4 ...

+... 5 ...+... 6 ...+... 7 ..*

 

A

T.Name++++++.Len++TDpB

......

Functions++++++++++++++++++++*

 

A

 

R FORMAT

 

 

 

 

PFILE(ORDDTLP)

 

A

 

 

 

 

 

 

 

 

TEXT('Access Path for Indexed +

 

A

 

 

 

 

 

 

 

 

File')

 

A

 

FLDA

 

 

14

 

 

 

 

A

 

ORDER

 

5

 

 

 

 

A

 

ITEM

 

 

5

 

 

 

 

A

 

FLDB

 

 

96

 

 

 

 

A

 

K ORDER

 

 

 

 

 

 

A

 

K ITEM

 

 

 

 

 

 

 

 

 

 

Figure 142.

(Part 1 of 2). Using Data Description Specifications to Define the Access

(Composite Key)

for

an

Indexed

File

In

this

example,

the

data

description specifications define two key

record

format

FORMAT

in

the

logical file ORDDTLL. For the two fields

as a composite key for a program described indexed file, the key contiguous in the record.

Chapter 16. Accessing Database 289Files

Page 312 Page 314
Page 313
Image 313
IBM AS/400 manual Keyword specifies position 15 as the starting po, Logical file ORDDTLL. For the two fields
Page 312 Page 314

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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