IBM AS/400 manual Examples of Sequential-by-Key Processing, Disk

Methods

for

Processing

Disk

Files

If,

in

the

same

job or activation group, two logical files use the

and

one

file

is

processed consecutively and one is processed for r

record

can be updated

that

has

already been

placed

in

the

buffe

to

the

program.

In this case, when the record

is

processed

from

file, the

record does

not reflect

the

updated

data.

To

prevent t

CL

command

OVRDBF

and

specify

the

option

SEQONLY(*NO),

which

indicates

that

you

do

not

want

multiple

records transferred

for a consecutivel

For more information on sequential only processing,DB2 UDBsee forthe AS/400

Database Programming.

Sequential-by-Key Processing

For	the sequential-by-key method of processing, records are read fr
key	sequence.

The sequential-by-key method of processing is valid for keyed files primary, secondary, or full procedural files.

For

output files

and for

input files

that

do not

use

random

functions

SETLL,

SETGT,

CHAIN,

or

ADD) and

that

have only

one

record

format,

the

I

RPG compiler defaults to or operates

as

though

SEQONLY(*YES)

had

been

fied on the CL command OVRDBF. (The

ILE

RPG

compiler does

not

operat

though SEQONLY(*YES) had been specified

for

update

files.)

SEQONLY(*YES)

allows multiple records to be placed

in

internal

data

management

buffe

records

are then

passed

to

the

ILE

RPG

compiler

one

at

a

time

on

If, in the same job, two files use the same physical file, and o

sequentially and one is processed		for	random	update,	a	record	could
that has already been placed in		the buffer that is presented to
case, when the record is processed from the sequential file,							the
reflect the updated data. To	prevent		this	problem,	use	the CL	comma
and specify the option SEQONLY(*NO),		which indicates that you do					not w
tiple records transferred for	a	sequentially		processed		file.

For more information on sequential only processing,DB2 UDBsee forthe AS/400

Database Programming manual.

Examples of Sequential-by-Key Processing

The following three examples show you different ways of using the sequential-by-key method of processing data.

DATA DESCRIPTION SPECIFICATIONS (DDS):Figure 144 on page 294 and

Figure 145 on page 294 shows the data description specifications (DDS

physical files used by the examples.	Figure 146 on page 294 shows t
the logical file used by the first	three examples.

Chapter 16. Accessing Database 293Files