Re: %lookup on a Data Structure Array

[Rory Hewitt <rory.hewitt@xxxxxxxxx>]

Try this:

    D ds_Cust      DS                  Qualified Inz
    D   array                          Dim( 50000 ) Ascend
    D    Cust                       3p 0 Overlay(Array)
    D    Cycle                     1a    Overlay(Array:*Next)

Rory

On Thu, Nov 10, 2011 at 9:09 AM, Kurt Anderson <kurt.anderson@xxxxxxxxxxxxxx
> wrote:

> I'm trying to reduce some program I/O for program processing millions of
> records.  I've identified a file that I feel could be loaded into an array
> instead of having the program chain out for every record.  Usually this
> file is between 100-1000 records.  However one of our clients has 20,000
> records in the file.  So before making the change, I decided to do a little
> reading on %lookup, to make sure I'd be using it correctly.
>
> http://www.ibmsystemsmag.com/ibmi/developer/rpg/iSeries-EXTRA--Look-Before-You--Lookup/
>
> It turns out that I had misunderstood how to trigger the binary search
> with a %lookup.  I thought sorting the array was enough, however to get the
> binary search one needs to explicitly specify Ascend or Descend on the
> array.
>
> So I went to add Ascend to a data structure array, and it won't let me:
>     D ds_Cust      DS                  Qualified Inz Dim( 50000 ) Ascend
>     D  Cust                         3p 0
>     D  Cycle                       1a
> Error:  RNF3501E Keyword is not allowed for a data-structure definition;
> keyword is ignored.
>
> I tried adding the Ascend keyword to the subfield that I use in the
> lookup, but it doesn't like that either (I wasn't expecting this to work,
> but at this point I'm grasping at straws).
>
> I suppose I could make these two fields their own arrays.  Though I'm not
> really a fan of that.  I love using data structures to group like-data
> together.
>
> Is there any way to get the new data structure array lookups to use a
> binary search?
>
> Kurt Anderson
> Sr. Programmer/Analyst
> CustomCall Data Systems
>
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