To improve the flexibility of your RPG coding, and to help protect the integrity of the calling program's data, learn to use read-only reference where appropriate.

Written by Bryan Meyers and Jim Buck

Editor's note: This TechTip is an excerpt from the book Programming in RPG IV, 4th Edition.

Prototypes provide an effective way to describe the data items to be passed between programs. Prototypes also offer some flexibility in the method the system will use to pass those parameters.

Use these techniques to ensure that you're writing effective and appropriate comments in your RPG code.

Written by Bryan Meyers and Jim Buck

Editor's note: This TechTip is an excerpt from the book Programming in RPG IV, 4th Edition.

Good programming style can serve a documentary purpose in helping others understand your source code. But use comments judiciously. If you practice good code construction techniques, you'll find that "less is more" when it comes to commenting the source. Too many comments are as bad as too few. Here are some specific commenting guidelines.

One trick in date/time arithmetic is learning to create and use durations.

Written by Joe Pluta

In the bad old days of RPG, dates and times were stored as pure numbers, and we had to work pretty hard to do any arithmetic. Time values were tough: when incrementing times, we had to roll the seconds into minutes and minutes into hours when either one hit 60, and then roll the hour at 24. Figuring out the number of seconds between two times was fun as well.

Date and time math is simple with %DIFF.

Written by Joe Pluta

This TechTip introduces you to the %DIFF BIF, a powerful function that allows you to find the difference between any two compatible date or time variables (including timestamps). This is just one more reason to start using real time and date variables in your programs and your database definitions!

There's no need to be afraid. Learn how to use RPG to load and extract binary data to and from DB2 BLOB columns.

Written by Gene Cobb

While vampires and zombies are all the rage these days, menacing invaders from outer space used to be the fright night monster du jour. Remember The Blob starring Steve McQueen? While this terrifying, bubbly alien may conjure up images of panic-stricken people running frantically through the streets, the database BLOB is actually something that should be…well…embraced!

This simple service program makes dBASE file access simple.

Written by Mike Faust

dBASE has been around since the late 1970s/early 1980s. It was the first widely used relational database for PCs. I recently had a need to import data into the System i from the U.S. Census Bureau's Tiger database, which stores address data for all of the United States, including state, county, and city. The Tiger database is made up of multiple dBASE format files, so I needed to create a means by which I could read the data directly from the System i. In this tip, we'll take a look at a simple service program that gives you the ability to do sequential data reads from a dBASE file.

After measuring 12,000 projects, a leading researcher reveals his findings.

Written by Steve Kilner

Maintenance and enhancement projects for legacy systems are notorious for being budget busters and deadline killers. This article gives a quick overview of how you can significantly improve the success rate of such projects. For more information, you can also watch these short videos: Using Complexity Analysis to Lower Project Costs and Hyper-Navigation of RPG Systems.

Manipulate and protect data quickly and easily.

Written by Issak Brender

There are many ways in modern RPG/RPGLE to manipulate data: BIFs, data structures, whole programs. This TechTip demonstrates examples of character string manipulations with XLATE operation code.