AS400 to IBM i: And we're just getting started

Video featuring Steve Will, chief architect of IBM i, and Alison Butterill, product offering manager for IBM i, showing ways IBM i clients have innovated over the past 30 years.

Runs just over 1 hour.

Hosted by HelpSystems, recorded July 18, 2018.

Using reference fields

When I first started programming on the AS400 the biggest improvement I encountered, compared to the System/36, was the external database. No longer did I have to have file specifications in my RPG programs, and I now had the ability to define fields by referencing another. Over the years I have used the referencing ability whenever I can had to define fields in files or variables in my RPG programs. By using reference fields makes database changes easier as a field's definition is changed in one place, then by recompiling all of the objects with the referencing, the new objects all have the new definition of the field in them.

In the past fortnight I have been asked several times about using reference fields, and in my experience there are many more who would like to ask the same question but feel intimated to do so. Therefore, I am writing this post to give examples of how I use them and why I do things the way I do.

All well-built databases have a data dictionary that defines the types of all the fields, or columns, within it. On AS400 and IBM i many of us achieved something similar using a reference file. This file contains the definition of every type of field that could be contained in any of the other files in the application.

IBM i 7.3 TR5 and 7.2 TR9 announced

The awaited announcement of new Technical Refreshes for IBM i 7.3, TR5, and 7.2, TR9, has been made. So what's new?

On the hardware side is the announcement of the Power9 chip based IBM Power E980 model 9080-M9S server.

I am not going to list all the changes on the software side just those that catch my eye at first glance.

Copying any data to and from a file in the IFS

In previous posts I have shown how to write SQL data to a file in the IFS and then how to retrieve the XML data from an IFS file, but what about just plain old text?

In this post I am going to keep the example as simple as possible so that you can see how easy this is. I am going to write three strings of data, "records", to an IFS file, retrieve the data from the file, then move each the "record" into an array. Some of what I am describing here I have also mentioned in my earlier posts, but I think it is valuable to have it in here too.

My example program is only 32 lines, which goes to show easy this is. All the hard work is performed by Db2 for i.

Using SQL UDF with RPG

This short post comes from a discussion I was having with two other IBM i developers at my place of work. I had shown them a number of SQL User Defined Functions, UDF, I had created to make my SQL statements easier.

"That's fine," started one of the developers, "but how does that help me in RPG. Won't I have to duplicate the procedures so I can call them in RPG?"

"No", I replied, "you can call them using SQL".

At first they were skeptical. Having shown them how easy it was to do they were sold.

Getting data from a XML file using SQL

A couple of months ago I write a post about creating XML from an IBM i hosted file and write it to a file in the IFS. It was obvious to me that I would have to write this post, describing how to get data from the XML file using SQL.

I could extract the data from the XML file in the IFS using the RPG operation code XML-INTO, but I want to use SQL to do this.

Where to start? I guess with the XML data. The XML file, xmlfile.xml, is in my folder, MyFolder, in the IFS. It contains the same data I used in the post about writing to the XML file. In the file the data is not formatted, it is just one long string of data.

Using an output queue to send spool files to another partition

The germ of the idea for this post came from a conversation I was having with two other programmers I work with. The conversation became finding an easy way to transfer spool files from a development IBM i partition to a production partition.

Where I work there are multiple partitions on one PowerSystems server. These partitions are used by various subsidiary companies in different parts of the USA, and three locations in Europe. If a modification is made to a spool file layout, for example: invoice, how do I show a user in Germany or Illinois what this new layout looks like when I am in California? The development partition does not connect to all the printers used, as we do not want test data printing on a "live" printer when testing. In my experience if I copy the spool file to a PDF the user is not convinced. The only way they will be convinced that the change works is for it to print on their printer.

Securing DDM files

Using DDM files is a very easy way to access data from another IBM i. I frequently use them to pass data from one IBM i partition to another and back.

All I need to do is to create the DDM file with the following command and be able to access the data in the file SOMEFILE in the library SOMEIB in the IBM i partition RMTSYS.

Create DDM File (CRTDDMF) Type choices, press Enter. DDM file . . . . . . > DDMFILE Library . . . . . > QTEMP Remote file: File . . . . . . . > SOMEFILE Library . . . . > SOMELIB Remote location: Name or address . > RMTSYS Type . . . . . . . . . *SNA *SNA, *IP

Different types of numbers in files and tables

In a previous post I wrote about the different types of numbers that could be used in RPG. Alas, we have been spoiled with RPG as there are less types to choose from in when defining numbers fields in DDS files and columns (SQL) DDL tables.

 

DDS files

DDS files come in different forms, and they all have their own rules as to the types of numbers are valid. I am only going cover the major types, which in my opinion are:

1. Physical files
2. Display files
3. Printer files

30th anniversary of AS400 launch

There has been a lot of fanfare about this year being the 30th anniversary of the launch of the AS400, the esteemed ancestor of the IBM i operating system. Many others have written tomes about what this anniversary means to them, and I thought I would add a few thoughts of my own.

On June 21 1988 the server and operating system that had be known by insiders as Silverlake was launched to the world as the AS400. It was the brain child of Dr Frank Soltis to create a system for midsized businesses.

Different types of numbers in RPG

For those of you like me who have been programming in IBM i and its predecessors for some time this might seem a simple subject matter. But I have received quite a few questions regarding numbers in the past few weeks. So I thought I would write something answering those questions and a bit more about the different types of numbers you will find in IBM i.

The most basic types of numbers everyone who has programmed on an IBM i has used are packed and zoned numbers. Zoned numbers are not anything new they are just the name that is used for what we use to call signed numbers. What is the difference? Why would I want to use packed rather than zoned? It really comes down to space. Back when computer first started using disk storage it was very expensive, therefore, everyone tried to reduce the amount of disk space they use. Someone came up with the idea of "packing" numbers to reduce the amount of space they use. "Packing" is a method I can store two numbers in each byte. Rather than spend paragraphs explaining what this is I think an example, like a picture, paints a thousand words.

Using Built–in global variables

I wrote about creating my own global variables in the past, but I failed to mention the "built-in" ones. A global variable is a SQL variable you can create, place a value into, and then use within the same session. This is a great way to pass SQL variables from one program or procedure to the next. When the SQL session ends the variables are return to their default. If I change a global variable in one job, it does not change the value in the global variable in another job.

What I failed to mention in that post is since IBM i 7.2 there are some "built-in" global values that contain system information, and are maintained by the operating system. This allows me to get the values from these global variables and use them in my own programs and procedures. These built-in global variables can be found in two libraries, SYSIBM and QSYS2, I have no idea why IBM decided to split them between the two.

As with the user created global variables they are all CLE service programs: