vsampart2u4

Fundamentals of VSAM Part 2

© Copyright IBM Corp., 2000, 2004. All rights reserved.

MVS/ESA Fundamentals of VSAM Part 2

© Copyright IBM Corp., 2000, 2004. All rights reserved. of 31

UNIT Practical VSAM Applications

� VSAM Applications

Topics:



In this unit, you will learn how to use IDCAMS to create a KSDS file statement that defines a VSAM file.

This unit also demonstrates how to process a KSDS file.

Unit Introduction

Unit: Practical VSAM Applications



At the end of this unit, you will be able to:

• Explain how to use IDCAMS to create a KSDS file statement that defines a VSAM file

• Explain how to process a KSDS file statement using a program written in a language such as OS/VS COBOL or COBOL II

Unit Objectives




UNIT Practical VSAM Applications

� VSAM Applications

Topics:



At the end of this topic, you will be able to:



Topic Objectives

Unit: Practical VSAM Applications Topic: VSAM Applications

Introduction



Creating a KSDS File Statement

This example shows a partial record layout of a KSDS customer master file.

The records are 120 byte, fixed length records. CUST – ACCT is the primary key here.

Continued…


CUST-ACCT PIC X(06).

CUST–TYPE PIC X(01).

CUST-NAME PIC X(38).

.

.

.

.

Topic: VSAM Applications

Concepts



Creating a KSDS File Statement (cont’d)

This example shows a basic set of IDCAMS commands and parameters to create a KSDS.

A continuation character is needed to continue an IDCAMS command on a new line. Otherwise, IDCAM will flag it as an error.

Continued…


DEFINE CLUSTER _

(NAME(KISVS.CUST.CLUSTER) _

CYLINDERS (4 1) _

VOLUME (TESTO8) _

INDEXED) _

DATA

(NAME(KISV,CUST,DATA) _

RECORDIZE(120 120) _

KEYS (6 0)) _


Concepts




Beginning with the DEFINE command, identify the VSAM object to be defined. The general form is:

DEFINE object

Use the NAME parameter to give the VSAM object a name. It should be placed immediately after the object definition. Continued…


DEFINE CLUSTER _



Concepts




Indicate how much space the cluster will need. The space parameter can be expressed in CYLINDERS, TRACKS or RECORDS, depending on the size of the cluster.

Continued…


DEFINE CLUSTER _


CYLINDERS (4 1) _

VOLUMES(TESTO8) _


Concepts




The RECORDSIZE parameter specifies both the average and the maximum length of the data records.

The general form is:

RECORDSIZE(avg-length max-length)

Continued…


DEFINE CLUSTER _


CYLINDERS (4 1) _

VOLUMES (TEST08) _

RECORDSIZE(120 120) _


Concepts




Tell IDCAMS what the key length is and its relative position in the record. The general form is:

KEYS(length offset)

The other parameter for the cluster is the INDEXED parameter, which indicates that the VSAM file is a KSDS. It is the default and does not need to be coded. Continued…


DEFINE CLUSTER _


CYLINDERS (4 1) _

VOLUMES(TEST08) _


KEYS(6 0) _

INDEXED)


Concepts




Next, the data and index components of the cluster needs to be defined and named.

This completes the job.

The example here shows a complete IDCAMS statement that defines a VSAM file.

Continued…


DEFINE CLUSTER _

NAME(KISVS.CUST.CLUSTER) _

CYLINDERS (4 1) _

VOLUMES(TEST08) _


KEYS(6 0) _

INDEXED) _

DATA _

(NAME(KISVS.CUST.DATA)) _


Concepts




The example shows the format of another IDCAMS command REPRO. REPRO performs the following tasks:

• It loads a VSAM file.

• It makes a copy of a VSAM file. Continued…


REPRO INDATASET (entry-name) or

INFILE (ddname)

OUTDATASET (ENTRY-NAME) or

OUTFILE (ddname)

O SKIP (count)

P PROMKEY (key)

T FROMNUMBER (number)

I

O COUNT (count)

N TOKEY (key)

A TONUMBER (number)

L TOADDRESS (address)

REUSE . NORUSE

REPLACE . NOREPLACE


Concepts




Here is an example of a REPRO command that can be used to load a KSDS from a sequential file.

Continued…


REPRO INDATASET(KSVS.MAST.TRAN) _

OUTDATASET(KSVS.MAST.CLUSTER)


Concepts




The rest of the parameters for REPRO are optional.

To load a part of the file, use the parameter to establish a range for both input and output data sets. The example here shows code for the same.

Continued…


Input:

SKIP(no.-records-to-skip)

FROMKEY(key-value) KSDS or ISAM

FROMNUMBER(RELATIVE-RECLORD-NUMBER)

RRDS only

FROMADDRESS(relative-byte-address) KSDS

or ESDS only

Output:

COUNT (no.-records-to-be-copied)

TOKEY(key-value) KSDS or ISAM only

TONUMBER (relative-record-number)

RRDS only

TOADDRESS(relative-byte-address) KSDS or

ESDS only


Concepts




This example shows the REPRO command defined with a range of records skipped (SKIP) and copied (COUNT).

Continued…


REPRO INDATASET(KSVS.MAST.SEQ) _

OUTDATASET(KSVS.CUST.MAST) _

SKIP(100)

COUNT(500)


Concepts




Use the REUSE parameter to specify that a file may be loaded even if the output file already contains records, if it is specified earlier in the DEFINE CLUSTER command.

The REPLACE option is a method for dealing with KSDS duplicate methods.

Continued…


DEFINE CLUSTER _

NAME(KSVS.CUST.CLUSTER) _

REUSE

REPRO INDATASET(KSVS.TRAN) _

OUTDATASET(KSVS.CUST.CLUSTER)

REUSE


Concepts




To see any data after it is loaded, use the PRINT command. This dumps the contents of the data set in CHARACTER, HEX or DUMP format.

Continued…


PRINT INDATASET (entry-name) or

INFILE (ddname) (format)

Input:

SKIP(no.-records-to-skip)

PROMKEY (key-value) KSDS or ISAM

FROMNUMBER (relative-record-number)

RRDS only

FROMADDRESS (relative-byte-address)

KSDS or ESDS only

Output:

COUNT (no.-records-to-be-copied)

TOKEY (key-value) KSDS or ISAM only

TONUMBER (relative-record-number)

RRDS only

TOADDRESS (relative-byte-address)

KSDS or ESDS only_


Concepts




This example shows the LISCAT, ALTER and DELETE commands.


LISCAT ENTRIES (KISVS.CUSTOMER.*)

ALTER KSVS.CUSTOMER.DATA

INHIBIT

DELETE

KSVS.CUSTOMER.CLUSTER _

CLUSTER _


Concepts



Processing a KSDS

This example shows the complete PROCEDURE DIVISION of a program to load a sample KSDS with records.

Continued…


PROCEDURE DIVISION.

OPEN INPUT IN-FILE OUTPUT CUST-MAST.

IF CUST-STATUS NOT – 00

DISPLAY ERROR OPENING KSDS

DISPLAY STATUS IS CUST-STATUS

ELSE

READ IN-FILE

AT END SET END-OF-FILE TO TRUE

END READ

PERFORM UNTIL END-OF-FILE OR ERROR

MOVE IN-RECORD TO MASTER-REC

WRITE MASTER-RECORD

EVALUATE CUST-STATUS

WHEN 00

READ IN-FILE

AT END SET END-OF-FILE TO TRUE

END READ

END-PERFORM.

CLOSE IN-FILE CUST-MAST

IF CUST-STATUS NOT – 00

DISPLAY ERROR CLOSING KSDS

DISPLAY STATUS IS CUST-STATUS

END-IF

STOP RUN.


Concepts



Processing a KSDS (cont’d)

This example shows a SELECT statement to use for sequential access.

DATA DIVISION and WORKING STORAGE is also shown.

Continued…


SELECT CUST-MAST ASSIGN TO CUSTMAST

ORGANIZATION IS INDEXED

ACCESS MODE IS SEQUENTIAL

RECORD KEY IS CUST-ACCT

FILE STATUS IS CUST-STATUS.

DATA DIVISION.

FD CUST-MAST

LABEL RECORDS ARE STANDARD

01 MASTER-RECORD.

.

.

10 CUST-ACCOUNT PIC X(6).

10 CUST-REMAINING PIC X(114)


Concepts




The example shows the PROCEDURE DIVISION statements to read this file.

Continued…


100-MAIN.

OPEN INPUT CUST-MAST.

IF CUST-STATUS NOT = 00

abend program.

200-READ

READ CUST-MAST

EVALUATE CUST-STATUS’

WHEN 10

SET END-OF-FILE TO TRUE

ELSE

other processing options.


Concepts




To retrieve a record randomly, the program moves the desired key into the key of the KSDS.

In this example the abbreviated FDs have been used for both a TRAN-FILE and CUST-MAST.

The TRAN-FILE contains a sequential file of the keys to be randomly retrieved.

Now here are the PROCEDURE DIVISION statements. Notice the TRAN-KEY is moved to the CUST-ACCT before CUST-MAST is read.

Continued…


FD TFAN-FILE

LABEL RECORDS ARE STANDARD.

01 TFAN-REC.

05 TFAN-KEY PIC X(6).

05 TFAN-REMAIN PIC X(114).

FD CUST-MAST

LABEL RECORDS ARE STANDARD.

01 MASTER-RECORD...

10 CUST-ACCT PIC X(6).

10 CUST-REMAIN PIC X(114).

100-MAIN.

OPEN INPUT CUST-MAST, TFAN-FILE.

IF CUST-STATUS – 00

PERFORM 200-READ UNTIL EOF OR

EAD-ERROR....

200-READ.

READ TFAN-FILE

AT END SET EOP TO TRUE

IF NOT EOP

MOVE TFAN-KEY TO CUST-ACCT

READ CUST-MAST......


Concepts




This example shows a technique for the REWRITE statement to update a VSAM file. The VSAM file needs the OPEN I-O statement, so that it can be open for input and output.


100-MAIN.

OPEN INPUT TFAN-FILE.

OPEN I-0 CUST-MAST.

IF CUST-STATUS – 00

PERFORM 200-UPDATE UNTIL EOF OR EAD-ERROR....

200-UPDATE.

READ TFAN-FILE AT END ....

IF NOT EOF

MOVE TFAN-KEY TO CUST-ACCT

READ CUST-MAST

IF CUST-STATUS = 00

(perform update processing)

REWRITE MASTER-RECORD

(do REWRITE error processing)

ELSE

(do READ error processing).


Concepts



Now that you have completed this topic, you should be able to:



Topic Summary

Unit: Practical VSAM Applications Topic: VSAM Applications

Summary



Now that you have completed this unit, you should be able to:



Unit Summary


Summary

vsampart2u4

Documents

vsam file

vsam object

copyright ibm

ksds customer master

cust acct

unit introductionunit

osvs cobol

cobol iitopic objectivesunit