IBM AS/400 Sequential File, Record Address File, Using Program-Described Disk Files, D K1, D K2

Using Program-Described Disk Files

On the file description specifications, the length of the key field positions 29 through 33 (the combined number of positions required for and ITEM fields). The starting position of the key field is described keyword KEYLOC (starting in position 44). The starting position must specif first position of the first key field.

*..

1

...+

... 2

...

+...

3 ...

+

... 4 ...

+...

5 ...

+

6

+

7

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*

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

FORDDTLL

IP

F

120

10AIDISK

KEYLOC(15)

*..

1

...+

... 2

...

+...

3 ...

+

... 4 ...

+...

5 ...

+...

6 ...

+...

7

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*

DName+++++++++++ETDsFrom+++To/L+++IDc.Keywords+++++++++++++++++++++++++++++

DKEY

DS

D K1

1

5

D K2

6

10

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1

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... 2

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+...

3 ...

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7

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CL0N01Factor1+++++++Opcode(E)+Factor2+++++++Result++++++++Len++D+HiLoEq.￿

...

C

MOVE

ORDER

K1

C

MOVE

ITEM

K2

C

KEY

CHAIN

ORDDTLL

99

Figure

143.

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

(Composite

Key)

for

an

Indexed

File

When the DDS specifies a composite key, you must build a search arg program to CHAIN to the file. (A KLIST cannot be used for a program-d file.) One way is to create a data structure (using definition spec fields equal to the key fields defined in the DDS. Then, in the cal subfields equal to the value of the key fields, and use the data-st the search argument in the CHAIN operation.

In this		example, the MOVE operations set	the subfields K1 and K2 equ
value	of	ORDER and ITEM, respectively. The	data-structure name (KEY) is
used	as	the search argument in the CHAIN	operation.

Sequential File

Sequential files are files where the order of the records in the f order the records are placed in the file (that is, in arrival seque the tenth record placed in the file occupies the tenth record posit

Sequential	files		can be		processed randomly by relative record number,
utively,	or	by	a	record-address		file. You can use either the SETLL o
tion code		to set		limits	on the	file.

Record Address File

You can use a record-address file to process another file. A record contain (1) limits records that are used to process a file sequentia

(2)relative record numbers that are used to process a file by rel

numbers. The record-address file itself must be processed sequentially

A record-address file is identified by an R in position 18 of								the
ifications. If the record-address file contains					relative	record		number
must	contain a T. The	name	of the file to	be	processed	by	the	rec
must	be specified on	the	file description	specification.		You	identify

keyword RAFDATA( file-name).

290 ILE RPG for AS/400 Programmer's Guide