Moving content of data structure into an array

I have been asked this same question a few times during the last couple of weeks: What is easiest way to move data from a data structure's subfields into an array?

Asking some other people I know how they would do it, several of them did not know of this simple way.

Here is the start of my code:

Removing duplicate characters from a string

I was asked how I would remove duplicate characters from a string just using RPG. I has been some time since I came up with an all RPG solution, so I accepted the challenge.

The string of data is in a file, TESTFILE, in the field F1. The sample string I used in F1 was:

SELECT F1 FROM TESTFILE ; F1 -------------------- abcdefghabcdijkl

I have more than one of these characters in the string: a, b, c, and d. And only one of these: f, g, h, i, j, k, and l. My goal is for a single character of all of these.

Extra parameters added to Call command to prevent decimal data error

Anyone who has programmed on IBM i has experienced this frustration. I want to call a CL program from a command line. I type:

CALL CL_PGM ('A' 12)

And I am presented with the following error:

MCH1202 received by procedure CL_PGM. (C D I R)

For the beginner this is cryptic. When I drill down into the job log I can see what really happened:

More fun with the Boolean data type

IBM i 7.5 introduces a synonym for NULL, UNKNOWN. Having performed a few tests, I can confirm I can use it just as I would NULL.

For example I can use it when inserting data into a SQL Table. The first column in this Table is a Boolean data type, the second is character.

INSERT INTO QTEMP.TESTTABLE VALUES('true','1'),('false','2'),(DEFAULT,'3'), ('true','4'),('false','5'),('true',UNKNOWN)

I have used a multiple rows insert to insert six rows with one Insert statement. Notice how I have used UNKNOWN in the data for the last row to be inserted.

I check the contents of this file with the following SQL statement:

New data type for SQL - Boolean

A new data type has been added to Db2 for i's Data Definition Language, DDL, as part of IBM i 7.5, but was not added to IBM i 7.4 TR6. A Boolean data type.

Being Boolean it should only contain two values, but this can contain three possible values:

1. True
2. False
3. Null – when this contains no data

I love this. For many, many years I have been creating "Boolean" like columns or fields to contain a sorta kinda true/false logic. But as the columns/fields were either character or numeric they could contain any valid value of that data type. Now I can have a column to denote things like:

• Item is in-stock
• Item is in a backlog status
• Certain information has been provided or accompanies whatever

You get the idea.

A Boolean column can be defined in a SQL table as simply as:

9 years and counting!

Wow! It was nine years ago I wrote the first post of this blog. Here I am almost 800 posts later and I am still writing. Fortunately, IBM has "cooperated" and has released a lot of really interesting and exciting things in this time, giving me lots of material to write about.

This where I pick my favorite five posts of the past 12 months, which is always a struggle as there is always so many things to consider:

New RPG op-code to send messages to job log

Another addition to the RPG programming language with IBM i 7.5 and 7.4 TR6 is an operation code that allows me to write to the current job's job log.

I have been using the SQL procedure LPRINTF to write to the job log since 2019. Now I have the ability to do so with native RPG.

The new operation code is called Send Message, SND-MSG, and is accompanied by two new optional Built in Functions, BiF: %MSG and %TARGET.

Just how simple it is to write to job log I will demonstrate below. Let me start with my first example program's source code:

01 **free 02 dcl-s Text varchar(50) inz('Second message') ; 03 snd-msg 'First message' ; 04 snd-msg Text ; 05 snd-msg *INFO 'Third message' ;

New SQL built in function allows for validating data types

I am sure many of us have found that when we try and cast, in SQL, from one data type to another the “casting" will fail. This is especially true when moving character representations of numbers or dates to a decimal or date type. With the new release IBM i 7.5 and 7.4 TR6 there is a new SQL built in function that allows for the testing of a cast before it is performed.

Before I start explaining this new built in function let me define the table I will be using, TESTTABLE:

CREATE TABLE MYLIB.TESTTABLE (COLUMN1 CHAR(10), COLUMN2 CHAR(10)) ;

It has two columns I will be using in this post. For now, I am only interested in the contents of the column COLUMN1, which I can see using the following SQL statement:

Updated IBM i roadmap for 2022

With IBM i 7.5 being released IBM has updated its IBM i Roadmap image:

Click on image to see larger version

I find interesting:

Start testing the new date rule

Since the beginning of time on OS/400, the beloved ancestor of IBM i, six long dates have always used the "1940 rule" to determine the century.

If Year >= 40 then Century = 19
If Year < 40 then Century = 20

2039 is not that far in the future, only 17 years away, IBM has developed a replacement rule, "1970 rule".

If Year >= 70 then Century = 19
If Year < 70 then Century = 20

As part of the IBM i 7.5 announcement IBM has said that the new rule will be implemented in a future release or Technology Refresh.

IBM is giving a foretaste of the new rule in 7.5. I used the word "foretaste" as the "1940 rule" has not been replaced, but the new rule can be implemented on top of it, if you so desire. The rule can either be applied to your entire system, which I do NOT recommend, or it can be implemented just to the current job.

TR PTFs for 7.4 and 7.3 available today

The PTFS for the two new Technology Refreshes:

• IBM i 7.4 TR6
• IBM i 7.3 TR12

Are now able for download as PTFs from IBM Support website.

Start planning to download these into a test partition, and get ready for the testing process to validate your applications with these TRs. Don't forget the database (SQL) and RPG PTFs come separately.

<whispers> It might be time to get the latest CUM PTFs to ensure you get all the available PTFs for your release </whispers>

New way in RPG to monitor for errors

In RPG we have been able to monitor for errors, using a Monitor group, for years. Until IBM i 7.5 and 7.4 TR6 we could only monitor for program and file status codes. I have always preferred CL’s MONMSG that allowed me to monitor by message id instead.

As part of the new release, or new TR for 7.4, there is a new RPG operation code, ON-EXCP, that can be used within a Monitor group to monitor for a specific error message or messages. The syntax is very similar to that of the ON-ERROR operation code:

monitor ; Something on-excp 'CPF1234' : 'RNX1234' : 'RNQ1234' ; Do something else to mitigate the error endmon ;

I am going to give some examples below so you can understand how ON-EXCP works. Here is my RPG program’s source code: