Dynamically specify files in RPG without the use of embedded SQL.

Written by Tom Snyder

Do you have physical files with the same file format that are separated into multiple physical files--whether it be for legal reasons, query speed, or storage archiving--which requires you to keep modifying your programs when the new files are created? This article will show you how to continue creating new physical files, without the need for additional program compiling and maintenance.

Modernization is one way to enhance the value of an application, but reducing back-end maintenance expense is a close second.

Written by Chris Smith

The trend toward modernization of RPG legacy systems is in full swing largely because companies realize it makes more sense economically to upgrade the front-ends of these applications than it does to rewrite or replace them. What you don't hear much about, however, is the job of maintaining the back-end of these programs that may have been written 20 years ago.

RPG steals a trick from its older brother COBOL to make moving data just a little bit easier.

Written by Joe Pluta

Practical programming is often about the little things. For example, one of the issues in programming multi-tiered applications is moving data between tiers. In message-based programming, you can and should reduce the number of traveling fields by using a data structure that contains only the fields you need. The problem is that you have to populate those fields with individual MOVE instructions and, with large tables, identifying every field can be tedious and error-prone (especially when the fields have short names). EVAL-CORR gets around that problem.

Sometimes an old technique with a new tweak is the best answer. This article shows you how to externally describe multi-format flat files from partners or legacy systems.

By Joe Pluta

It's often the little things that can make a big difference in the world of RPG, and often an older technique can come to the rescue when dealing with the thorny issues of the real world. A perfect example is dealing with flat files having multiple formats. While externally described files can't handle them, a mix of old and new techniques can give you the next best thing.

Bust out your old trig textbooks to write some great code.

By Ron Koontz

As programmers, we're often challenged with unusual requests, and we have to find creative ways to solve the problem.

Here is one such challenge. Based on the client's legacy code, we need to calculate mileage between two cities. The legacy code has a file, but it's not always populated correctly.

Another trick with arrays is sizing them. This article shows you how to size your arrays dynamically.

By Joe Pluta

In an earlier article, I showed you how to initialize arrays and how to sort them based on a subfield. I did this with fairly small arrays, where you could easily define the values for the array in your D-specs. The next trick is trying load arrays from disk. You don't know how many you will load, and you really don't want to allocate the memory for the entire array.