  Editing RMS relative and indexed files? 
 The Question is:
 
Is there a way to edit a file that is in a relative organized file?
 
 The Answer is :
 
  There is no standard OpenVMS utility that can accomplish the task
  of (directly) editing a relative-format file.
 
  There are data manipulation products (DATATRIEVE, ACCELR) for sale
  and potentially freeware that may help.
 
  The OpenVMS Wizard would encourage you to write a simple program in
  the language of your choice (either a compiled language, DCL, or
  otherwise) to perform the required edits while maintaining the
  file integrety from the perspective of the file contents.  Alternatively,
  write a tool that can export the data into a (sequential) file that can
  be edited, and a tool that then imports the data into the appropriate
  format.
 
  For INDEXED files containing (only) text data, you can potentially edit
  the file with a regular text editor and reconverting the output back to
  indexed using an FDL description obtained from the original. There are
  caveats with this: order of duplicates, and you must be exceedingly
  careful to avoid altering other data or other columns in the file.
 
  For RELATIVE files, a sequential view of the file as seen by a regular
  text editor or 'TYPE' commands will drop the cell-level information.
  In other words, the file will be packed and all records will appear
  densely populated (in adjacent cells) while the relative file may
  actually have been sparely populated. As long as the input file was
  tightly packed, with no deleted records or empty record cells, then
  you can reconvert the edited contents, but such simple cases are rare
  applications.
 
  For occasional edits or data recovery purposes on relative-format and
  indexed-format files, the most common tool is often a simple (and
  custom-written) DCL command procedure.  Using the WRITE/UPDATE command,
  you can update a previously read record IN PLACE. Using READ/DELETE you
  can remove record, but you can not add new records (no WRITE/KEY)
  To read the target record, either use sequential reads (READ with no
  argument other than handle and buffer) until the right count or
  contents is seen. Or... use KEYed reads, but those are tricky at best
  due to the BINARY nature of relative file record numbers.
 
  Some sample manipulations are included below. The output is based on
  a file loaded with record 1,5 and 9 using the included simple BASIC
  load program.  Use DUMP/RECORD[=(star:nn,count:mm)] to verify the CELL
  number in the RFA.
 
 
$ create/fdl=sys$input tmp.rel
file; organization relative
record; size 80
$ run load
$ open/read/write x tmp.rel
$ read x rec
$ show sym rec
$ read x rec
$ show sym rec
$ write /update x "hello there"
$ close x
$ typ tmp.tmp
aap                 test
hello there
mies                test
$ dump/rec tmp.tmp
 
Record number 1 (00000001), 80 (0050) bytes, RFA(0001,0000,0000)
 
 20202020 20202020 20202020 20706161 aap              000000
 20202020 20202020 74736574 20202020     test         000010
 20202020 20202020 20202020 20202020                  000020
 20202020 20202020 20202020 20202020                  000030
 20202020 20202020 20202020 20202020                  000040
 
Record number 2 (00000002), 11 (000B) bytes, RFA(0005,0000,0000)
 
            657265 6874206F 6C6C6568 hello there..... 000000
 
Record number 3 (00000003), 80 (0050) bytes, RFA(0009,0000,0000)
 
 20202020 20202020 20202020 7365696D mies             000000
 20202020 20202020 74736574 20202020     test         000010
 20202020 20202020 20202020 20202020                  000020
 20202020 20202020 20202020 20202020                  000030
 20202020 20202020 20202020 20202020                  000040
 
$ open/read/write x tmp.tmp
$ key="1234"
$ key[0,32]=5
$ read/key=&amp;key x rec
$ show symb rec
  REC = "hello there"
$ key[0,32]=6
$ read/key=&amp;key x rec
%RMS-E-RNF, record not found
$ write/update x "Hmmmm...."
%RMS-F-CUR, no current record (operation not preceded by $GET/$FIND)
 
$ type load.bas
 
	open "tmp.rel" as file #1, recordtype any, ORGANIZATION RELATIVE, map x
	map (x) string x=20, y=20
	y = "test"
	input "record number"; i
	while i
	  input "record data"; x
	  put #1, record i
	  input "next record"; i
	next
	close #1
 
 
 
 Answer written or last revised on  17-APR-2002 
