Re: Reading using SQL and dealing with nulls

Alternatively to Birgittas suggestion, you can also fix the “null problem” with the use of a SQL function - like this:

exec sql select ifnull(field_name, ‘’),
…..
into :rpg_field
from …..;

With ifnull(), nvl() or coalesce() you can “replace” Null values with another value, so that you don’t need to code null indicators.

HTH
Daniel

Am 03.02.2022 um 19:13 schrieb Birgitta Hauser <Hauser@xxxxxxxxxxxxxxx>:

Define an Array with NULL indicators (Int(5)) one element per column.
Initialize your output Data Structure before reading the data into the data
structure. If NULL values are passed, the appropriate Indicator in the
indicator array is set to -1, but the Output Fields are not changed.
So if you had initialized the data structure before, the Data-Structure
Sub-Fields have the default values.

Example:

DCL-DS YourOutputDS ...
End-DS;

DCL-S YourOutputInd Int(5) Dim(NbrOfDSSubfields);

Clear YourOutPutDS;
Clear YourOutputInd;
Exec SQL Fetch Next From YourCsr
Into :YourOutputDS :yourOutputInd; // Attention no Comma
between DS and Indicator Array!!!
//Check SQLCODE or SQLSTATE
//You may check if a NULL value is returned
If YourOutputInd(1) = -1; //Null Value in the first column.

BTW it is also possible to update or insert a complete row.
If a NULL value has to be written the appropriate Indicator has to be set to
-1.

Mit freundlichen Grüßen / Best regards

Birgitta Hauser


"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"
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-----Original Message-----
From: RPG400-L <rpg400-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of
dfreinkel@xxxxxxxxxxxxxxxxx
Sent: Donnerstag, 3. Februar 2022 19:00
To: 'RPG programming on IBM i' <rpg400-l@xxxxxxxxxxxxxxxxxx>
Subject: Reading using SQL and dealing with nulls

I am reading a system view in RPG.

Some of the fields have nulls.

I do not want to recode the data structure to ignore these fields as I may
need them.



Is there a way to tell the compiler to initialize these fields?



TIA



Darryl Freinkel

A4G

Telephone: 770.321.8562 Mobile: 678.355.8562



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