CKWRITE

Procedure CKWRITE copies a logical record from the program's data area to an output or an input/output KSAM file.

CALL "CKWRITE" USING filetable, status, record, recordsize

A call to procedure CKWRITE may be used to write records to a KSAM file either in sequential order or randomly by key value. The file must have been opened for output or for input/output, but not for input only.

Parameters

filetable: An 8 halfword record containing the number and name of the file, its input/output type, access mode, and a code indicating whether the previous operation on the file was successful and if so what, it was.
status: One halfword (two 8-bit characters) set to a pair of values upon completion of the call to CKWRITE to indicate whether or not the record was successfully written and if not, why not.
record: A record defined in the WORKING-STORAGE SECTION containing data to be written to the file by CKWRITE.
recordsize: An integer (S9(4)COMP) containing the length in characters of the record to be written. It must not exceed the maximum record length established for the file when it was created, and it must be long enough to contain all the keys.

Operation Notes

The file to which the content of record is written must be open for output only if sequential mode is specified. It may be opened for output or input/output if the access mode at open is random or dynamic.

When the file is opened for sequential access (access mode = 0) and for output only (I-O type = 1), then records must be written to the file in ascending sequential order by primary key value. The value of the primary key in the record to be written must be greater than the value of the primary key in any record previously written to the file. This ensures that the records written to the file are initially in ascending order physically as well as logically.

When I-O type = 1, CKWRITE writes records starting at the beginning of the file, thereby effectively clearing any records previously written to the file.

In a file opened for random or dynamic access (access mode = 1 or 2) and for output only or for input/output (I-O type = 1 or 2), records can be written in any order. The value of the primary key need not be in any particular relation to the primary key values of previously written records.

If you want to preserve existing records in the file, you should open the file with the input/output type equal to 2; when input/output type = 1, all existing records are cleared prior to the write.

If the file was opened for shared access with CKOPENSHR, then you must lock the file with a call to CKLOCK before writing any records. After the records are written, you should unlock the file with a call to CKUNLOCK.

The invalid key condition (left byte of status=2) can occur as a result of the following circumstances:

File was opened for sequential access in output mode and the value of the primary key in the record being written is less than or equal to the value of the primary key in the record just written; status=21.
File was opened for sequential or random access in output or input/output mode and the value of the primary key is equal to the value of the primary key in an existing record; status=22.
File was opened for sequential or random access in output or input/output mode and the value of an alternate key for which duplicates are prohibited equals the value of a corresponding key in an existing record; status=22.
File was opened for sequential or random access in output or input/output mode and an attempt was made to write a record beyond the physical bounds of the file; status=24.

Assume a KSAM file called KSAMFILE with records containing 74 characters, one primary key containing a name, and an alternate key containing a phone number. The data is read from an input file called DATA-FILE. (Refer to Figure A-2 “Representation of KSAMFILE Used in COBOL Examples” for a diagram of the structure of this file.)

The first example writes data to KSAMFILE in sequential order by the primary key.


DATA DIVISION 
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WORKING-STORAGE SECTION. 
77  RECSIZE        PIC S9(4)     COMP VALUE 74. 
77  RESULT         PIC 9(4)      VALUE 0. 
01  REC. 
  03  FILLER       PIC XX        VALUE SPACES. 
  03  NAME         PIC X(20). 
  03  PHONE        PIC X(8). 
  03  OTHERDATA    PIC X(44). 
01  DAT. 
  03  NAME         PIC X(20). 
  03  PHONE        PIC X(8). 
  03  OTHERDATA    PIC X(44). 
01  FILETABLE. 
  03  FILENUMBER   PIC S9(4)      COMP VALUE 0. 
  03  FILENAME     PIC X(8)       VALUE "KSAMFILE". 
  03  I-O-TYPE     PIC S9(4)      COMP VALUE 0. 
  03  A-MODE       PIC S9(4)      COMP VALUE 0. 
  03  PREV-OP      PIC S9(4)      COMP VALUE 0. 
01 STAT. 
  03  STATUS-KEY-1 PIC X. 
  03  STATUS-KEY-2 PIC X. 
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PROCEDURE DIVISION. 
START. 
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   MOVE 1 TO I-O-TYPE,<--- set type to output only 
   CALL "CKOPEN" USING FILETABLE, STAT. 
   IF STATUS-KEY-1="O" THEN GO TO WRITE-F. 
   DISPLAY "CKOPEN ERROR, STATUS = ", STAT. 
   IF STATUS-KEY-1= "9" THEN 
      CALL "CKERROR" USING STAT, RESULT 
      DISPLAY "CKERROR NO. ", RESULT. 
   STOP RUN. 
WRITE-F. 
   READ DATA-FILE INTO DAT; 
      AT END GO TO FINISH. 
   MOVE CORRESPONDING DAT TO REC. 
   CALL "CKWRITE" USING FILETABLE, STAT, REC, RECSIZE. 
   IF STATUS-KEY-1="0" THEN 
      DISPLAY REC. 
      GO TO WRITE-F. 
   IF STAT="21" THEN 
      DISPLAY "SEQUENCE ERROR IN", NAME OF REC 
      GO TO WRITE-F. 
   IF STAT = "22" THEN 
      DISPLAY "DUPLICATE KEY", NAME OF REC 
      GO TO WRITE-F. 
   IF STAT = "24" THEN 
      DISPLAY "END OF FILE" 
      GO TO FINISH. 
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FINISH 
   CLOSE DATA-FILE. 
   CALL "CKCLOSE" USING FILETABLE, STAT. 
   IF STATUS-KEY-1="9" THEN 
      CALL "CKERROR" USING STAT, RESULT 
      DISPLAY "CKCLOSE ERROR NO. ", RESULT. 
   STOP RUN.

The second example, using the same DATA DIVISION and the same FINISH procedure, writes one record to the file containing "ADAMSON JOHN" as its primary key value.

 
PROCEDURE DIVISION. 
START. 
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  MOVE 1 TO I-O TYPE.<--- output only 
  MOVE 2 TO A-MODE.<--- random access 
  CALL "CKOPEN"USING FILETABLE, STAT. 
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. check status 
FIND-REC. 
  READ DATA-FILE INTO DAT; 
     AT END GO TO FINISH. 
  IF NAME OF DAT = "ADAMSON        JOHN" THEN 
     GO TO WRlTE-REC; 
     ELSE GO TO FIND-REC. 
WRITE-REC. 
  MOVE CORRESPONDING DAT TO REC. 
  CALL "CKWRITE" USING FILETABLE, STAT, REC, RECSIZE. 
  IF STATUS-KEY-1="0" THEN 
     DISPLAY REC," RECORD WRITTEN" 
     GO TO FINISH. 
  IF STAT = "22" THEN 
     DISPLAY "DUPLICATE KEY" 
     GO TO FINISH. 
  IF STAT = "24" THEN 
     DISPLAY "NO ROOM IN FILE" 
     GO TO FINISH.

CKWRITE

Technical documentation

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Parameters

Operation Notes