Re: RPG IV program - comments requested

[Jim Langston <jlangston@xxxxxxxxxxxxxxxx>]

Yes, I agree with you, but in this particular case this is a rather small
transmission
file (less than 1000 records) that will soon be cleared, and the operation as it
is
takes an unnoticeable amount of time.

This brings up a good point, though, as a lot of times I will have to mass 
change

records, and since we don't have SQL I have to write a program to do it.  And
a lot of times I will open the file UP and then just do something like:

if    CMCONT = 'ABCD123456' or
      CMCONT = 'BCDE234567' or
      CMCONT = 'CDEF345677'
      EVAL     SomeDate = 990101
      UPDATE   CMFILE1
      ENDIF

and I can see where there are problems with this.  First, it is taking me a long
longer
than needed to cycled through all my records just to find some specific ones.
Second,
on the read of all those records, since I am opening it as UP, as someone 
stated,
I am
putting a record lock on each record in the file, however briefly.

I really don't see that I should create a large program for these types of one
time updates
though.  And, also, sometimes I may not have all the key information to build a
key to
SETLL and start from there.  Building a logical that the AS/400 would have to
maintain
and I would probably not use for quite a while doesn't make much sense either.

Regards,

Jim Langston

Scott Mildenberger wrote:

> The code itself looks fine but a comment on how the program operates.  The
> program reads through the whole file to update only a subset of records.
> Depending on the number of records in the file this could be very
> inefficient.  It would be better to create a logical file keyed by BSXTRL
> and then use Trailer to SETLL and then use READE to only read the records
> from the file that you need to update.  We always try and avoid reading
> through the entire file unless we are doing something to all (or most) of
> the records.  If a program reads all the records in a file then it's
> performance will get worse as the file contains more records.
>
> Scott Mildenberger
>
> > -----Original Message-----
> > From: Jim Langston [SMTP:jlangston@conexfreight.com]
> > Sent: Friday, September 24, 1999 9:39 AM
> > To:   RPG400-L@midrange.com
> > Subject:      RPG IV program - comments requested
> >
> > This is a small update utility I just created for one of my users.  All
> > it does is
> > goes through a file and changes one field (BSSCAC) when another filed is
> >
> > equal to an input value (BSXTRL).
> >
> > There are two input parameters, Trailer and SCACCode.  Trailer is the
> > search
> > criteria.
> >
> > I would request critiquing of this program.  That is, I am using D specs
> > to declare
> > my variables, I am using a PLIST to declare my entry parameters and I am
> > using
> > the RPG Cycle to cycle through all my records.
> >
> > Since I am just starting to program in RPGLE I do not want to get any
> > bad habits
> > started now.  I would rather start of on the right foot.
> >
> > So I guess I am asking, if you were to write this same program, is this
> > the way you
> > would code it?
> >
> > Regards,
> >
> > Jim Langston
> >
> >      FBSSHIPX   UP   E             DISK
> >
> >      DTrailer          S             10A
> >      DSCACCode         S              4A
> >
> >      C                   IF        Trailer = BSXTRL
> >      C                   EVAL      BSSCAC = SCACCode
> >      C                   UPDATE    BSSHIPX1
> >      C                   ENDIF
> >
> >       *******************************
> >       *** Set up Entry Parameters ***
> >       *******************************
> >      C     *INZSR        BEGSR
> >      C
> >      C     *ENTRY        PLIST
> >      C                   PARM                    Trailer
> >      C                   PARM                    SCACCode
> >      C
> >      C                   ENDSR
> >
> >
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