• Admin Alert: When System Job Tables Attack, Part III

  October 8, 2008 Joe Hertvik

  In the last two issues, I discussed i5/OS problems that occur with system job table overflows, and how overflows can hurt your system. This week, I’m wrapping up the series by going over my own recent experience with job table overflows. I’ll also share some excellent reader advice on job tables that’s been coming into my mailbox lately. What Are System Job Tables; The Short Version System job tables are internal system objects that i5/OS uses to track partition jobs. There can be up to 10 job tables on a partition, and the maximum number of system jobs

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• Keep Your Hands on the Keyboard with RSE

  October 1, 2008 Susan Gantner

  Last year, I wrote up a tip with a list of some of my favorite keyboard shortcuts in Remote Systems Explorer (RSE). Later, a slightly longer list of my favorite shortcuts was published on our System i Developer Website as a downloadable list to print and pin up next to your workstation. Even using all those shortcuts, there are still many, many things we need to do while working with RSE that would require using a mouse–unless you know a few more shortcuts. So here are a few that you may find useful for those occasions that you want to

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• Simulate a Boolean Data Type in a Database Table

  October 1, 2008 Hey, Mike

  I want to create a column in an SQL table and only allow two values. They could be 1 or 0, Y or N, or whatever. I don’t want the database to allow any other values into the column. I want the default to be the “false” value. How would you define such a column in SQL? I understand that Oracle supports a BOOLEAN data type, but I don’t think such exists on the AS/400. —Guru Reader You are correct, SQL Server has the BIT data type and Oracle has the BOOLEAN data type but there is no equivalent

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• Admin Alert: When System Job Tables Attack, Part II

  October 1, 2008 Joe Hertvik

  Last issue, I discussed the ins and out of i5/OS system job tables and how job table overflows can hurt your system. This week, I’ll provide some advice on how to detect and delete excessive jobs that are cluttering your system. Next week, I’ll show you how to maintain the job tables and how to check for job table damage. What Are System Job Tables, Again? System job tables are internal system objects that i5/OS uses to track partition jobs. There can be up to 10 job tables on a partition, and the maximum number of system jobs for

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• Variable-Length Database Fields Better Use Disk Space

  September 24, 2008 Jon Paris

  In a recent tip, I discussed the use of variable length fields in building strings within RPG programs. This time, I will focus on how these fields can be utilized in our databases and consider the trade-offs, between disk space and performance, involved. Why would you want to use a variable length field? Well, how about product descriptions as one example, or notes fields associated with an order? The marketing department would probably like to have an unlimited number of characters to play with, but they may accept a limit of say 1,000 as more realistic. The problem, of course,

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• Common Table Expressions Ease System Conversion

  September 24, 2008 Dear Occupant

  In the factory where I work, we are replacing one engineering module of the large ERP package we run with a more modern, more robust engineering module. What was one physical file is now two or three physical files. Modifying programs and queries to use the new files is just about more fun than I ever envisioned when I was learning to write RPG at the vo-tech many years ago. Fortunately, I have some great tools to help with the conversion. One of them is the common table expression. I’ll show you what I mean. Assume a customer master file,

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• Admin Alert: When System Job Tables Attack, Part I

  September 24, 2008 Joe Hertvik

  Vigilance pays, negligence punishes. Want proof? Try ignoring i5/OS message CPI1468 (System job tables nearing capacity) the next time it shows up. A system job table overflow can prevent your system from accepting new jobs, delete your spooled files, fill up your DASD, or stop an IPL. And those are its good points. This week and next, I’ll look at system job table overflows and how they affect your system. What Are System Job Tables and Why Should I Care? System job tables are internal system objects used by the i5/OS operating system to track every job on a partition.

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• The Efficiency of Varying Length Character Variables

  September 10, 2008 Jon Paris

  Remember the bad old days when dinosaurs still roamed the earth and the only way to build strings in RPG involved playing silly games with arrays? Or worse still, obscure combinations of MOVE operations? Thankfully those days are far behind us–although sadly there are still a few RPG/400 dinosaurs coding away! RPG IV introduced many powerful new string handling options, such as the %TRIMx family of BIFs, but even now there are capabilities in the language that few programmers fully exploit. One of my favorites is variable length fields. There are many good reasons to use these fields, but in

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• SQL Assist: Powerful Interactive SQL

  September 10, 2008 Skip Marchesani

  The Run SQL Scripts function, a.k.a. the SQL Script Center or Script Center, is System i Navigator’s counterpart to Interactive SQL on the green screen side of the System i. The SQL Script Center allows the user to execute all or a subset of a script that contains one or more SQL statements and/or batch CL commands. It is part of the Navigator Database function and is an extremely powerful and flexible tool with lots of function that can have a very positive impact on application developer productivity. Interactive SQL has a very good multilevel SQL prompter that supports a

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• Admin Alert: Getting into a i5/OS Restricted State

  September 10, 2008 Joe Hertvik

  There’s a special place for restricted state processing in the i5/OS or OS/400 world. In restricted state, administrators can apply upgrades, change core system parameters, backup the operating system and run special commands that affect partition configurations. This week, I’ll examine everything about restricted state processing, from why it exists, to how to enter and leave this core operating system function. The Beauty of Restriction Some i5/OS functions can’t be run while the system is active. That’s why IBM created restricted state processing, a feature that isn’t available in many other operating systems. Restricted state occurs when you end all

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