File 在COBOL中创建一个文件

使用COBOL，如果指定名称的文件不存在，如何创建line sequential.dat文件

使用

OPEN OUTPUT fd

每次删除任何现有数据时，都会创建一个新文件，或者在文件控制选择短语中添加可选的关键字

ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    select OPTIONAL data-file
        assign to file-name
        organization is line sequential
        file status is data-file-status.

并使用打开I-O数据文件。如果需要，COBOL将为第一次写入准备一个空文件

有关任意示例，请参见（不是按直线顺序排列，但应使点穿过）

为完整起见，此处包含清单（和输出）：

OCOBOL >>SOURCE FORMAT IS FIXED
      *> ***************************************************************
      *><* ================
      *><* indexing example
      *><* ================
      *><* :Author:    Brian Tiffin
      *><* :Date:      17-Feb-2009
      *><* :Purpose:   Fun with Indexed IO routines
      *><* :Tectonics: cobc -x indexing.cob
      *> ***************************************************************
       identification division.
       program-id. indexing.

       environment division.
       configuration section.

       input-output section.
       file-control.
          select optional indexing
          assign to "indexing.dat"
          organization is indexed
          access mode is dynamic
          record key is keyfield of indexing-record
          alternate record key is splitkey of indexing-record
              with duplicates
          .

      *> ** OpenCOBOL does not yet support split keys **
      *>  alternate record key is newkey
      *>      source is first-part of indexing-record
      *>                last-part of indexing-record
      *>      with duplicates

       data division.
       file section.
       fd indexing.
       01 indexing-record.
          03 keyfield          pic x(8).
          03 splitkey.
             05 first-part     pic 99.
             05 middle-part    pic x.
             05 last-part      pic 99.
          03 data-part         pic x(54).

       working-storage section.
       01 display-record.
          03 filler            pic x(4)  value spaces.
          03 keyfield          pic x(8).
          03 filler            pic xx    value spaces.
          03 splitkey.
             05 first-part     pic z9.
             05 filler         pic x     value space.
             05 middle-part    pic x.
             05 filler         pic xx    value all "+".
             05 last-part      pic z9.
          03 filler            pic x(4)  value all "-".
          03 data-part         pic x(54).

      *> control break
       01 oldkey               pic 99x99.

      *> In a real app this should well be two separate flags
       01 control-flag         pic x.
          88 no-more-duplicates          value high-value
             when set to false is              low-value.
          88 no-more-records             value high-value
             when set to false is              low-value.

      *> ***************************************************************
       procedure division.

      *> Open optional index file for read write
       open i-o indexing

      *> populate a sample database
       move "1234567800a01some 12345678 data here" to indexing-record
       perform write-indexing-record
       move "8765432100a01some 87654321 data here" to indexing-record
       perform write-indexing-record
       move "1234876500a01some 12348765 data here" to indexing-record
       perform write-indexing-record
       move "8765123400a01some 87651234 data here" to indexing-record
       perform write-indexing-record

       move "1234567900b02some 12345679 data here" to indexing-record
       perform write-indexing-record
       move "9765432100b02some 97654321 data here" to indexing-record
       perform write-indexing-record
       move "1234976500b02some 12349765 data here" to indexing-record
       perform write-indexing-record
       move "9765123400b02some 97651234 data here" to indexing-record
       perform write-indexing-record

       move "1234568900c13some 12345689 data here" to indexing-record
       perform write-indexing-record
       move "9865432100c13some 98654321 data here" to indexing-record
       perform write-indexing-record
       move "1234986500c13some 12349865 data here" to indexing-record
       perform write-indexing-record
       move "9865123400c13some 98651234 data here" to indexing-record
       perform write-indexing-record

      *> close it ... not necessary, but for the example
       close indexing

      *> clear the record space for this example
       move spaces to indexing-record

      *> open the data file again
       open i-o indexing

      *> read all the duplicate 00b02 keys
       move 00 to first-part of indexing-record
       move "b" to middle-part of indexing-record
       move 02 to last-part of indexing-record

      *> using read key and then next key / last key compare
       set no-more-duplicates to false
       perform read-indexing-record
       perform read-next-record
           until no-more-duplicates

      *> read by key of reference ... the cool stuff
       move 00 to first-part of indexing-record
       move "a" to middle-part of indexing-record
       move 02 to last-part of indexing-record

      *> using start and read next
       set no-more-records to false
       perform start-at-key
       perform read-next-by-key
           until no-more-records

      *> read by primary key of reference
       move "87654321" to keyfield of indexing-record

      *>
       set no-more-records to false
       perform start-prime-key
       perform read-previous-by-key
           until no-more-records

      *> and with that we are done with indexing sample
       close indexing

       goback.
      *> ***************************************************************

      *><* Write paragraph
       write-indexing-record.
         write indexing-record
             invalid key
                 display
                     "rewrite key: " keyfield of indexing-record
                 end-display
                   rewrite indexing-record
                       invalid key
                           display
                               "really bad key: "
                               keyfield of indexing-record
                           end-display
                   end-rewrite
         end-write
       .

      *><* read by alternate key paragraph
       read-indexing-record.
           display "Reading: " splitkey of indexing-record end-display
           read indexing key is splitkey of indexing-record
         invalid key
             display
                "bad read key: " splitkey of indexing-record
             end-display
               set no-more-duplicates to true
           end-read
       .

      *><* read next sequential paragraph
       read-next-record.
           move corresponding indexing-record to display-record
           display display-record end-display
           move splitkey of indexing-record to oldkey

           read indexing next record
               at end set no-more-duplicates to true
               not at end
                   if oldkey not equal splitkey of indexing-record
                       set no-more-duplicates to true
                   end-if
           end-read
       .

      *><* start primary key of reference paragraph
       start-prime-key.
           display "Prime < " keyfield of indexing-record end-display
           start indexing
              key is less than
                  keyfield of indexing-record
              invalid key
                  display
                      "bad start: " keyfield of indexing-record
                  end-display
                  set no-more-records to true
              not invalid key
                  read indexing previous record
                      at end set no-more-records to true
                  end-read
           end-start
       .

      *><* read previous by key of reference paragraph
       read-previous-by-key.
           move corresponding indexing-record to display-record
           display display-record end-display

           read indexing previous record
               at end set no-more-records to true
           end-read
       .
      *><* start alternate key of reference paragraph
       start-at-key.
           display "Seeking >= " splitkey of indexing-record end-display
           start indexing
              key is greater than or equal to
                  splitkey of indexing-record
              invalid key
                  display
                      "bad start: " splitkey of indexing-record
                  end-display
                  set no-more-records to true
              not invalid key
                  read indexing next record
                      at end set no-more-records to true
                  end-read
           end-start
       .

      *><* read next by key of reference paragraph
       read-next-by-key.
           move corresponding indexing-record to display-record
           display display-record end-display

           read indexing next record
               at end set no-more-records to true
           end-read
       .
       end program indexing.
      *><*
      *><* Last Update: 20090220

---

前缀，因为WRITE INVALID KEY子句触发重写以允许重写密钥和数据。

我知道您的问题在这里已经很老了。但是今天我仍然有同样的问题，几个小时后我发现我正在使用的带有OpenCobolIDE 4.7.6的GnuCOBOL 2.0在尝试使用OpenExtend时产生了错误35。我以一种不太优雅的方式解决了它，但它工作得非常完美。我正在分享我找到的解决方案

   IDENTIFICATION DIVISION.
   PROGRAM-ID. CREATFIL.

   ENVIRONMENT DIVISION.
   CONFIGURATION SECTION.
   REPOSITORY.
       FUNCTION ALL INTRINSIC.
   INPUT-OUTPUT SECTION.
   FILE-CONTROL.
       SELECT FD-VIRTUAL ASSIGN TO "CADFILE.TXT"
       ORGANIZATION IS LINE SEQUENTIAL
       ACCESS MODE IS SEQUENTIAL
       FILE STATUS IS WS-GET-ERROR.

   DATA DIVISION.
   FILE SECTION.
   FD  FD-VIRTUAL.
   01  FS-BOOK.
       05 NOME PIC X(40).

   WORKING-STORAGE SECTION.
   77  WS-GET-ERROR      PIC XX.

   LOCAL-STORAGE SECTION.
   01  TB-VIRTUAL.
       05  TB-BOOK.
           10 LS-NOME    PIC X(40).
   77  LS-ENTER          PIC X.
   77  WS-RESP           PIC A VALUE "Y".

   PROCEDURE DIVISION.
       OPEN EXTEND FD-VIRTUAL.
       IF WS-GET-ERROR = "35" 
          OPEN OUTPUT FD-VIRTUAL
       END-IF
       IF WS-GET-ERROR = "00"
          PERFORM UNTIL UPPER-CASE(WS-RESP) NOT = "Y"
             DISPLAY X"0D"
             DISPLAY "Name: " WITH NO ADVANCING
             ACCEPT LS-NOME
             WRITE FS-BOOK FROM TB-BOOK
             DISPLAY "More record (Y) for YES " WITH NO ADVANCING
             DISPLAY "- any key for NOT: " 
                WITH NO ADVANCING
             ACCEPT WS-RESP
             IF UPPER-CASE(WS-RESP) NOT = "Y"
                EXIT PERFORM
             END-IF
          END-PERFORM
       END-IF.

       CLOSE FD-VIRTUAL.

       DISPLAY X"0D".
       DISPLAY "Press <ENTER> to finish... " WITH NO ADVANCING.
       ACCEPT LS-ENTER.
       STOP RUN.
   END PROGRAM CREATFIL.

---

这很有帮助。我希望IO能与行顺序文件一起工作，但它能工作。它应该与行顺序文件一起工作。此外，重写还可以成功地更新先前读取的记录。@Buggabill；是的，对不起，我想知道不同的文件结构是否会让人困惑。但是，我确实试着用。。。对于任意示例（不是按直线顺序排列，但应使点穿过）。我希望重点关注可选的和第二次运行的区别。

openi-O文件描述符

对可选的行顺序（至少在OpenCOBOL中）有效。从未在这些条件下测试过重写。可选的开放I-O将允许空的读取过程和写入时追加。我犯了一个错误。你没事。顺序行文件将与OPEN IO一起使用，如果文件不存在，OPEN OUTPUT将创建该文件。我的程序现在可以运行了。谢谢您使用哪种COBOL方言？对于所有COBOL方言，

可选

短语与

选择

一起使用时，可能不支持行顺序文件的输出。如果在运行程序之前xxxx.dat不存在，您认为这可能是一个问题吗？如果xxxx.dat在开始时不存在，它将在结束时存在。如果在开始时确实存在，那么在结束时，所有数据都将是“新”数据。这一切都很“正常”，所以你是说别的吗？

rewrite key: 12345678
rewrite key: 87654321
rewrite key: 12348765
rewrite key: 87651234
rewrite key: 12345679
rewrite key: 97654321
rewrite key: 12349765
rewrite key: 97651234
rewrite key: 12345689
rewrite key: 98654321
rewrite key: 12349865
rewrite key: 98651234

   IDENTIFICATION DIVISION.
   PROGRAM-ID. CREATFIL.

   ENVIRONMENT DIVISION.
   CONFIGURATION SECTION.
   REPOSITORY.
       FUNCTION ALL INTRINSIC.
   INPUT-OUTPUT SECTION.
   FILE-CONTROL.
       SELECT FD-VIRTUAL ASSIGN TO "CADFILE.TXT"
       ORGANIZATION IS LINE SEQUENTIAL
       ACCESS MODE IS SEQUENTIAL
       FILE STATUS IS WS-GET-ERROR.

   DATA DIVISION.
   FILE SECTION.
   FD  FD-VIRTUAL.
   01  FS-BOOK.
       05 NOME PIC X(40).

   WORKING-STORAGE SECTION.
   77  WS-GET-ERROR      PIC XX.

   LOCAL-STORAGE SECTION.
   01  TB-VIRTUAL.
       05  TB-BOOK.
           10 LS-NOME    PIC X(40).
   77  LS-ENTER          PIC X.
   77  WS-RESP           PIC A VALUE "Y".

   PROCEDURE DIVISION.
       OPEN EXTEND FD-VIRTUAL.
       IF WS-GET-ERROR = "35" 
          OPEN OUTPUT FD-VIRTUAL
       END-IF
       IF WS-GET-ERROR = "00"
          PERFORM UNTIL UPPER-CASE(WS-RESP) NOT = "Y"
             DISPLAY X"0D"
             DISPLAY "Name: " WITH NO ADVANCING
             ACCEPT LS-NOME
             WRITE FS-BOOK FROM TB-BOOK
             DISPLAY "More record (Y) for YES " WITH NO ADVANCING
             DISPLAY "- any key for NOT: " 
                WITH NO ADVANCING
             ACCEPT WS-RESP
             IF UPPER-CASE(WS-RESP) NOT = "Y"
                EXIT PERFORM
             END-IF
          END-PERFORM
       END-IF.

       CLOSE FD-VIRTUAL.

       DISPLAY X"0D".
       DISPLAY "Press <ENTER> to finish... " WITH NO ADVANCING.
       ACCEPT LS-ENTER.
       STOP RUN.
   END PROGRAM CREATFIL.

OPEN EXTEND FD-VIRTUAL.
IF WS-GET-ERROR = "35" 
   OPEN OUTPUT FD-VIRTUAL
END-IF