• Guru: When An Outer Join Is An Inner Join

  February 15, 2021 Ted Holt

  When is a boy not a boy? When he’s abed! When is a door not a door? When it’s ajar! When is an outer join not an outer join? (Sorry, no dad joke here. Three dad jokes in one paragraph would have been too many, don’t you agree?) Let me answer that last question.

  In my work I often see outer joins that are not really outer joins, but inner joins. Oh, based on what I’ve heard from IBM, the query engine may treat them as outer joins, but the result set is the same as that produced by an …

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• Guru: The Uncertainty of Redundant Row Selection

  February 8, 2021 Ted Holt

  Is redundancy good or bad? I say it depends. According to Nassim Nicholas Taleb, “Redundancy is ambiguous because it seems like a waste if nothing unusual happens. Except that something unusual happens — usually.” I have seen some unusual behavior when joining database tables, but try as I might, I can’t figure out what that unusual behavior depends on. Let me show you what I mean.

  First, we need some data for illustration. Let’s say that our company uses an ERP system that was designed for make-to-stock manufacturing. What the factory builds goes into the warehouse, and customer orders are …

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• Guru: A Philosophically Engineered Approach to the Processing of Parameters, Take Two

  February 1, 2021 Ted Holt

  A strange thing happened to me recently. I was writing a new program and like a good programmer, was not reinventing the wheel. I was calling a utility program that calculated the values I needed. However, this utility program, which had always worked correctly, was giving me invalid data. How is it possible that a program can work properly for a long time and suddenly go bad?

  The answer to this question was ably answered by Rick Cook, who wrote “Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying …

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• Guru: What’s Your RDi Preference?

  January 25, 2021 Susan Gantner

  To say that RDi is highly customizable is putting it mildly. There are hundreds of preferences to set as well as many other types of customizations that can be done. I’m often asked about my favorite preference settings and other customizations. This tip includes a few of the ways that my own workspace differs from the default “out of the box” RDi settings.

  In this tip I’ll concentrate on some of my favorite preference settings. In a later tip, I’ll continue the discussion on additional customizations I make in my RDi workspace using other methods besides the preferences dialogs.

  I’ll …

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• Guru: Fall Brings New RPG Features, Part 3

  January 18, 2021 Jon Paris

  In my previous tips (see Related Stories below), I covered the new BIFs and op-code options added with this release. This time I’m going to discuss a couple of new compiler options that focus on the conversion of character data to numeric.

  While you may not have needed these capabilities to date, it is highly likely that you will in the near future. Why? Because of the rapid growth in the use of web services in the IBM i world. I don’t think I have talked to a single client in the last 12 months who was not already providing …

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• Guru: Fall Brings New RPG Features, Part 2

  January 11, 2021 Jon Paris

  In my previous tip I outlined some of the new features added to RPG with the Fall 2020 release. In this and the following tip I will be covering the features that I ran out of space for in that first one.

  This time I will cover the new FOR-EACH loop construct. I have wanted this in RPG ever since encountering it in PHP. Simply put, it automatically iterates through an array, “serving up” one element at a time. When I say “an array” I mean any kind of array, including data structure arrays, dynamic arrays and even the new …

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• Guru: SQL and QTEMP

  January 4, 2021 Ted Holt

  Hey, Ted.

  For many years IBM i developers, operators, and others have taken advantage of an operating system feature called the QTEMP library. Through the years you have referenced it various times in IT Jungle as a useful feature of IBM i. I recently read an article in which a respected IBM expert from the Rochester lab services team told people not to use the QTEMP library when working in SQL. It would be very interesting if you could dive into this topic and explain when/if there is still a time and place for QTEMP. I think a lot of …

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• Guru: Success Requires Many Teachers

  December 14, 2020 Ted Holt

  I am not a “super programmer”- if such a thing even exists. I am not a genius, nor am I a guru. I’m not an expert. Whatever success I have had as a computer programmer these years, I attribute to a very few causes. I would like to end this year by writing about two of them.

  Number 1: I have learned, often the hard way, how to keep myself out of trouble. My code is dull and bland and boring, and I like it that way. I strive to make my code straightforward, honest, and so easy to understand …

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• Guru: Fall Brings New RPG Features

  December 7, 2020 Jon Paris

  In this time of pandemic we could all do with a little cheering up. So “Santa” Barbara (a.k.a. Barbara Morris) and the elves at the IBM Toronto Lab have delivered an early Christmas present. Available now via PTF for 7.3 and 7.4, there are some real gems in these latest RPG enhancements.

  For the most part, these enhancements assist in improving code readability. That is to say that they are not giving us completely new functionality in the way that (say) Open Access or DATA-INTO did. Rather they give us better, clearer ways of doing things. They have an additional …

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• Guru: SQL Writes CL

  November 30, 2020 Ted Holt

  SQL is the one tool I cannot work without. Take it away from me and I’ll start driving a truck for a living. Naturally I’m eager to find more ways to make SQL work for me. Today I’d like to share how I recently used SQL to write a huge CL command for me. This is a technique that’s good to know.

  My challenge was to copy all of the several hundred physical data files in a library to a save file so that those files could be loaded onto another IBM i system. The Save Library (SAVLIB) command was …

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