• Subject: Re: Multi-format logical files
  • From: Larry Bolhuis <lbolhui@xxxxxxx>
  • Date: Mon, 18 May 1998 09:15:44 -0400
  • Organization: Arbor Solutions, Inc

Joe Teff wrote:
> >> What is a multiformat logical file?

Another use that I have found for a multiformat LF is where a single
record in a file has more than one field that I want to key.  For
example three search fields: SRC1, SRC2, SRC3.  The multi can combine
the file to itself, three times with the fields SRC1, 2, and 3 as the
key for each inclusion respectively.  This allows a single index to
allow searching over all three fields.

Two problems to watch for:  1) In the maintenance (or DB Trigger)
program be sure that the three fields have different values (except for
blanks which are excluded) this assures that no single Physical record
can be selected more than once with a single search key.  2) In the DDS
(as seen below) you must name the fields to appear in each record, since
you cannot have the same record format in the LF three times.

          R IMF11801                  PFILE(IMP11801)  
              ... (include more fields here)
          K SRC1                                      
          O SRC1                      COMP(EQ '     ') 

          R IMF11802                  PFILE(IMP11801)  
          K SRC2                                      
          O SRC2                      COMP(EQ '     ') 

          R IMF11803                  PFILE(IMP11801)  
          K SRC3                                      
          O SRC3                      COMP(EQ '     ') 

    Larry Bolhius
    Arbor Solutions, Inc
    Grand Rapids, MI
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