October 17


Updating Numeric DTAARA in RPGLE

By NickLitten

October 17, 2014

RPGLE, dtaara

Numeric Data Areas are a little trickier than Alphameric

Updating any numeric DTAARA in RPGLE is slightly different in RPG /FREEFORMAT than in the good old fashioned column based RPG/400. Using RPG ILE, data structures are treated as character data. The nature of a data area is that its a string of data that can contain a mixture of various data formats.

If we play with the local data area (*LDA) its essentially a long string of stuff:

Updating numeric dtaara

Of course this string of data can be populated with a mixture of values:

Updating numeric dtaara in rpgle 1
*LDA populated with different datatypes

So, since a DataStructure in RPG is always character – how do we update a numeric only data area?

Read a simple Nine Character Numeric Data Area

Updating a Numeric Data Structure in RPG/FREE

Let’s stop my waffle and look at an example. That is why you are here after all.

I have a numeric DS called EMLRECNUM, cunningly designed to hold an increment count of the number of emails floated out into the ether.

Updating numeric dtaara in rpgle 2

Annoyingly I can define a Data Structure like this and it looks correct:

 dcl-ds EmlRecNum dtaara('EMLRECNUM') qualified;     
    count zoned(9:0);                                 
 end-ds ;    

and when I try to update it like this:

 in *lock EmlRecNum;       
 emlrecnum.count += 1;           
 out EmlRecNum;     

Most annoyingly it all compiles and looks/feels like a jolly simple peace of RPG code.

But when you run it… oh boy... big wet explosion follows:

Updating numeric dtaara in rpgle 3
Splattery death of updating a numeric DS

How do we fix this?

If the only thing in the DTAARA is a *DEC value, use a stand-a-lone field rather than a data structure:

dcl-s EmlRecNum packed(9:0) dtaara('EMLRECNUM'); 

We treat the update in the exact same way:

in *lock EmlRecNum;
   emlrecnum += 1;
out EmlRecNum;

And thats that.

But it made me scratch my head for waaay too long. So, I hope it helps some other propellor headed IBM-i programmer type chaps or chappettes or transchapperoons out there 🙂

  • In your example you change two things. You go from DS to single variable, but you also go from zoned to packed. *DEC is packed. Zoned is stored differently on disk so zoned wouldn’t work regardless. Just curious if you tried that and it still didn’t work?

  • {"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

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