HP 3000 Manuals HP 3000 Manuals
CKWRITE
Procedure CKWRITE copies a logical record from the program's data area to
an output or an input-output 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-word 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. (Refer to
Filetable Parameter discussion earlier in this section.)
status one-word (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. (Refer to Status Parameter discussion
earlier in this section.)
record a record defined in the WORKING-STORAGE SECTION
containing data to be written to the file by CKWRITE.
recordsize an interger (S9(4)COMP) containing the length in
characters of the record to be written.lt 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.
USING CKWRITE
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.
WRITING IN SEQUENTIAL MODE. 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 insures 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.
WRITING IN RANDOM MODE. 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.
WRITING WHEN ACCESS IS SHARED. 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.
INVALID KEY. 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".
EXAMPLES
Assume a KSAM file called KSAMFILE with records containing 74 characters
(72 characters of data following two characters reserved for the delete
code), 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 3-2 for a diagram of the structure of this file.)
The first example writes data to KSAMFILE in sequential order by the
primary key. The second example, using the same DATA DIVISION and the
same FINISH procedure, writes one record to the file containing the
"ADAMSON JOHN" as its primary key value.
1. Example of Sequential Write.
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.
2. Example of random write.
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
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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.
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