如何在z/OS上使用VSAM文件读取和写入记录

本代码演示如何在z/OS上使用VSAM文件读取和写入记录。VSAM（虚拟存储器访问方法）是IBM在z/OS操作系统中使用的文件存储和访问方法。本示例使用COBOL编写，展示了如何使用不同的VSAM操作来读取和写入记录。

IDENTIFICATION DIVISION.
PROGRAM-ID. VSAM-READ-WRITE.

*
* DECLARE FILE CONTROL BLOCKS
*
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    SELECT VSAM-FILE ASSIGN VSAM-FILE-NAME
    ORGANIZATION IS INDEXED
    ACCESS MODE IS RANDOM
    RECORD KEY IS VSAM-RECORD-KEY
    FILE STATUS IS VSAM-FILE-STATUS.

*
* DECLARE WORKING STORAGE
*
DATA DIVISION.
FILE SECTION.
FD  VSAM-FILE.
01  VSAM-RECORD.
    05  VSAM-RECORD-KEY           PIC X(08).
    05  VSAM-RECORD-DATA          PIC X(80).
WORKING-STORAGE SECTION.
01  WS-VSAM-KEY.
    05  WS-VSAM-KEY-LENGTH        PIC S9(5) BINARY.
    05  WS-VSAM-KEY-VALUE         PIC X(30).
01  WS-VSAM-FILE-STATUS            PIC X(02) VALUE SPACES.

PROCEDURE DIVISION.
*
* OPEN VSAM FILE
*
0000-MAIN.
    OPEN I-O VSAM-FILE.
    IF VSAM-FILE-STATUS NOT = '00'
       DISPLAY 'VSAM FILE STATUS: ' VSAM-FILE-STATUS
    ELSE
       MOVE 'KEY-VALUE' TO WS-VSAM-KEY-VALUE
       MOVE LENGTH OF WS-VSAM-KEY-VALUE TO WS-VSAM-KEY-LENGTH
*
* READ RECORD
*
0001-READ.
       READ VSAM-FILE RECORD INVALID KEY
           DISPLAY 'END OF FILE'
           GO TO 0003-EXIT.
       DISPLAY VSAM-RECORD.
*
* WRITE RECORD
*
0002-WRITE.
       MOVE SPACES TO VSAM-RECORD-DATA
       WRITE VSAM-RECORD INVALID KEY
           DISPLAY 'WRITE ERROR: ' WS-VSAM-FILE-STATUS.
       GO TO 0001-READ.
*
* CLOSE VSAM FILE AND EXIT
*
0003-EXIT.
    CLOSE VSAM-FILE.

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