• Guru: I’m A Number, You’re A Number, Everybody’s A Number

  September 9, 2019 Ted Holt

  Do you, like Bob Seger, sometimes feel that you are nothing more than a number? Me too. That’s because to many people, that’s exactly what we are. And if there’s one thing that computers are good at, it’s assigning numbers — to orders, to accounts, to invoices, to transactions, and of course, to people. Since we have to make the computer assign numbers, we may as well learn the modern way to do it.

  In my earliest days of programming, I would store the last assigned of a series of numbers in a data file. (The S/34 and S/36 …

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• Guru: Read a Data Area As a One-Row Table with SQL, Take Two

  August 26, 2019 Ted Holt

  Fifteen years ago, reader W.G. asked me about the possibility of treating a data area as a one-row table (a physical file with one record) in an SQL query. The question intrigued me because in my System/36 days, I had often wished that I could access the local data area (LDA) as a one-record data file in a query.

  Today, thanks to Scott Forstie and his team at IBM, I update my response to W.G. with more information. It’s not that the technique I presented in 2004 is outdated — it’s as relevant as ever — but that the fine …

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• Guru: Going Dark In RDi

  August 19, 2019 Paul Tuohy

  In this article I am going to show you how to configure RDi for dark mode. Dark mode is where the background of an application is changed from white to black. Some say that dark mode makes text (and especially code) easier to read. Others say it’s more difficult to read. Personally, I am a convert, but I know other developers who hate it. Maybe you should give it a try and see which you prefer.

  Recently, there has been a lot of debate about dark mode (mostly prompted by Apple introducing it as an option in its operating systems), …

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• Guru: RDi Code Coverage Without SEPs

  August 12, 2019 Susan Gantner

  My last Guru tip provided an introduction to RDi’s Code Coverage tool that you can use to determine how complete your tests are. In that tip I discussed how to run it using Service Entry Points (SEPs). In this follow-on tip, I’ll continue the exploration of this tool with some additional details plus introduce you to an alternative way to run a Code Coverage session.

  Before going into the alternative approach to running Code Coverage, there are a few details I didn’t mention in the first tip.

  I mentioned that Code Coverage uses the debug engine. What I didn’t mention …

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• Guru: Passing Parameters To Python

  August 5, 2019 Mike Larsen

  Python scripts offer great benefits to developers, whether used standalone or in conjunction with RPG programs. As I’ve been exploring Python and recently I had a need to execute a Python script from an RPG program. In addition to executing the script, I also wanted to pass it parameters.

  One of the benefits of passing parameters is to give us the ability to soft-code programs or scripts. Soft-coding makes programs more flexible and re-usable, and helps to reduce maintenance.

  To illustrate how to do this, I’ve coded a very simple RPG program and an even simpler Python script. I’ll start …

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• Guru: How Thorough Was Your Last Test? RDi Code Coverage Can Tell You

  July 22, 2019 Susan Gantner

  When you’ve made changes to one or more programs, you test all the changes – right? And, of course, you also test all the rest of the code just to make sure you didn’t break anything else. Did you do that with your last set of changes? Did you test ALL the code? Enabling you to answer that last question is what RDi’s Code Coverage facility is all about.

  This is an introduction to Code Coverage — the basics of both why and how to use it. Before I go into how to run it, it may pique your interest …

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• Guru: Finding Large Files With Python

  July 15, 2019 Mike Larsen

  It’s always a good idea to purge files that aren’t needed any longer. Chances are that you already have procedures in place to purge data from Db2 files and tables, but what about files that reside in the IFS? Do you have a good solution for keeping the IFS clean?

  Perhaps you have old order files stored in the IFS. If you work for a large company, these types of files can accumulate quickly. I’ve written processes in the past to remove files from the IFS using RPG, but I’d like to offer an alternative. I’m going to show how …

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• Guru: One Way To Deal With Two Null Formats

  July 8, 2019 Ted Holt

  Hey, Ted:

  We are building a new system and want to use modern programming and database techniques. I have had quite a time trying to get nulls to act right. It gets confusing fast because RPG handles them differently than the way embedded SQL does. When using SQL for I/O, how do we handle the two null formats?

  — Brian

  There are several ways to go about the “problem” of nulls. Let me give you one simple method, but keep in mind that it’s not the only way.

  First, let’s create a table and put some data into it.

  create 

  …

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• Guru: Use SQL to Generate Random Data

  June 17, 2019 Ted Holt

  Suppose I needed to generate a large database table with random data in order to adequately test the performance of an SQL query. Suppose that, for security reasons, I was not allowed to copy the production version of the table. Suppose that I needed a way to generate a lot — and I do mean a lot! — of random data. Suppose this scenario is not mere supposition.

  Before an SQL query goes into production, it should be tested against a production-like dataset. Running a query against a test dataset of 25 rows (records) can produce unpleasant surprises when it’s …

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• Guru: Getting Started With Python On IBM i

  June 10, 2019 Stephanie Rabbani

  Python is one of my favorite open-source languages. I’ve used it to build web applications, utilities, and diverse tools such as a web server monitor and an automated application testing suite. In this article, I’ll show you how to install Python on IBM i and create your first program.

  Why Python? For several reasons.

  • You can use Python to do some cool processing on your system. Graphical application development, games, data analysis, and web development are all Python’s strengths.
  • Coding in Python is easy, relatively speaking. The syntax is easy to learn, dropping the formal verbosity found in traditional

  …

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